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chore(deps): update dependency undici to v7.30.1 [security] - #1323

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chore(deps): update dependency undici to v7.30.1 [security]#1323
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This PR contains the following updates:

Package Change Age Confidence
undici (source) 7.29.1 → 7.30.1 age confidence

undici vulnerable to downstream response desynchronization via retry interceptor

CVE-2026-16728 / GHSA-8xcm-r25x-g524

More information

Details

Impact

Undici's interceptors.retry() can deliver a response whose body length does not match the Content-Length header exposed to the application after a retry or resume of a partial response. Applications that use interceptors.retry() and forward upstream response headers and bodies downstream, for example proxy or gateway applications, may emit an invalid HTTP response with a stale Content-Length header. This can lead to downstream response desynchronization, connection hangs, or response corruption in clients or intermediaries that rely on the forwarded framing metadata.

A malicious or faulty upstream can respond to a range request with a 206 Partial Content response such as:

Content-Range: bytes 0-99/300
Content-Length: 300

and then send only 99 bytes before closing the socket. interceptors.retry() can then retry with Range: bytes=99-99, receive the final byte, and deliver a 100-byte body to the application while the response headers still contain Content-Length: 300 from the first response.

The bug requires interceptors.retry() to be enabled, an upstream that returns a partial response with a mismatched framing header, and a downstream forwarder that does not remove or recalculate Content-Length.

Patches

Patched in undici v6.28.0, v7.29.0, and v8.9.0. Users should upgrade to one of these versions or later.

Workarounds
  • Disable interceptors.retry() for untrusted upstreams.
  • Remove or recalculate Content-Length before forwarding a response body assembled or transformed by Undici.

Severity

  • CVSS Score: 4.8 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to CRLF Injection via blob-like body 'type' property

CVE-2026-15157 / GHSA-m8rv-5g2x-5cg5

More information

Details

Impact

When an application passes a duck-typed blob-like body to undici's HTTP/1.1 dispatcher (via request(), stream(), pipeline(), or dispatch()) with a .type derived from untrusted input, an attacker can inject CRLF sequences (\r\n) to append arbitrary HTTP headers and potentially smuggle a second request past the upstream.

The vulnerable branch in lib/dispatcher/client-h1.js pushes body.type directly into the outgoing headers with no validation, while every other header path in undici goes through isValidHeaderValue():

} else if (util.isBlobLike(body) && request.contentType == null && body.type) {
  headers.push('content-type', body.type)  // bypasses isValidHeaderValue()
}

The bug requires a hand-rolled duck-typed blob object or a Blob subclass with a controlled .type. Native Blob is safe because its constructor strips CRLF from .type. fetch() is unaffected because it validates via the Headers class. Ecosystem consumers that build duck-typed blob shapes from user input include form-data-encoder, formdata-polyfill, and formdata-node.

Same defect class as CVE-2022-35948 (explicit content-type sink, fixed in undici 5.8.2) and CVE-2026-1527 (upgrade option sink, fixed in 6.24.0 / 7.24.0), both closed by adding isValidHeaderValue() on their respective sinks. This branch was missed.

Patches

Patched in undici v6.28.0, v7.29.0, and v8.9.0. Users should upgrade to one of these versions or later.

Workarounds
  • Set an explicit, validated content-type header on the request options (skips the vulnerable branch).
  • Use a native Blob (or fetch-blob) instead of a hand-rolled duck-typed object.
  • Reject control characters in the MIME type before assigning it to .type.
  • Use fetch() instead of the non-fetch APIs.

Severity

  • CVSS Score: 4.2 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to cookie attribute injection via unsanitized domain and unparsed setCookie fields

CVE-2026-16729 / GHSA-v3r7-h72x-cjcm

More information

Details

Impact

The setCookie function has two attribute injection paths. validateCookieDomain does not reject semicolons (validateCookiePath already does at 0x3B), so a domain value like example.com; SameSite=None lands verbatim as Domain=example.com; SameSite=None. The unparsed array's loop only checks each entry contains = and does not sanitize values, so an entry like X-Custom=val; HttpOnly lands unchanged, injecting HttpOnly without the caller setting cookie.httpOnly = true.

Applications that pass user-controlled input to these fields, typically multi-tenant or reverse-proxy servers that scope session cookies to a tenant-supplied domain, can have SameSite CSRF protections bypassed, Secure or HttpOnly forced or stripped, or the intended SameSite tier overridden.

Patches

Patched in undici v6.28.0, v7.29.0, and v8.9.0.

Workarounds
  • Sanitize domain values against the RFC 1034 letter-digit-hyphen set before passing to setCookie.
  • Do not pass user-controlled data to the unparsed field.

Severity

  • CVSS Score: 4.8 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to downstream response splitting via retry interceptor

CVE-2026-18540 / GHSA-r53p-7pc4-xj5r

More information

Details

Impact

Undici's interceptors.retry() can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a Content-Length, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded Content-Length, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).

For example, a 404 Not Found with Content-Length: 2 that sends one byte then closes can be resumed with an open-ended Range request, and the resumed 206 Partial Content bytes are appended, so the application receives more than two body bytes while still seeing Content-Length: 2. The bug requires interceptors.retry() enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate Content-Length.

Patches

Patched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrade to one of these or later.

Workarounds
  • Disable interceptors.retry() for untrusted upstreams, or set maxRetries: 0.
  • Remove or recalculate Content-Length before forwarding a response body assembled by Undici.

Severity

  • CVSS Score: 3.7 / 10 (Low)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to Subresource Integrity bypass via non-lowercase algorithm tokens

CVE-2026-109841 / GHSA-f72v-6w45-q472

More information

Details

Impact

undici's fetch() verifies Subresource Integrity (SRI) metadata by looking up the algorithm token in a lowercase-only set, but the SRI specification defines a valid token by its ASCII-lowercase form. A correct but non-lowercase token such as SHA256-... or Sha256-... is therefore treated as unknown and skipped. When no recognized algorithm remains, undici treats the integrity list as empty and accepts the response, so a server that returns a body different from the pinned digest passes the check.

An application that pins a response with a valid uppercase or mixed-case SRI token receives attacker-controlled bytes with no integrity error. The attacker needs only to control the response body, not the application's integrity metadata. The issue affects response integrity only. The regression was introduced in undici 7.15.0; releases 7.14.0 and earlier lowercase the token and are not affected.

Patches

Upgrade to 7.30.1 or 8.12.2. undici now normalizes the algorithm token to ASCII lowercase before validating it and before selecting the strongest algorithm, so case variants of SHA-256, SHA-384, and SHA-512 are verified correctly.

Workarounds

Use lowercase algorithm tokens (sha256, sha384, sha512) in integrity metadata.

Severity

  • CVSS Score: 5.9 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to Denial of Service via unbounded memory in the EventSource parser

CVE-2026-109924 / GHSA-4qv8-2p9j-2685

More information

Details

Impact

undici's EventSource client can be driven to exhaust process memory by a malicious or compromised Server-Sent Events peer. By sending millions of tiny completed data: fields with no blank event separator, or a single unfinished line split across many chunks, the parser retains a growing amount of per-field and per-chunk state. The byte-based maxEventSize and maxResponseSize limits do not bound that retained state, and maxResponseSize is enforced on the compressed body before decompression, so a small compressed response can expand into enough retained memory to terminate the process. The application only needs to maintain an EventSource connection to an untrusted peer, which controls only the response. Availability is the only impact.

Patches

Upgrade to 6.29.1, 7.30.1, or 8.12.2, which bound the retained EventSource parser state (the number of data fields and buffered chunks, the unfinished-line length, and per-field byte totals) independently of the byte limits.

Workarounds

None.

Severity

  • CVSS Score: 5.9 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to Denial of Service via unhandled error on excessive content-encodings

CVE-2026-109869 / GHSA-xjj6-f33q-929c

More information

Details

Impact

undici's fetch() crashes the Node.js process when a malicious server returns a response with more than five content codings and closes the connection before sending the body. undici rejects such responses (a content-encoding limit), but it created the internal response stream before that check and returned without attaching an error listener or aborting the request. The early close then surfaces a content-length mismatch on that orphaned internal stream, which Node.js treats as an unhandled error and terminates the process. A remote, unauthenticated server can trigger this with a single response, even when the application correctly catches the fetch() rejection. undici 6.x, 7.x, and 8.x are affected.

Patches

Upgrade to 6.29.1, 7.30.1, or 8.12.2. undici now validates the content-encoding chain before creating the internal body stream and aborts the response when the limit is exceeded, so no error can surface on an orphaned stream.

Workarounds

None.

Severity

  • CVSS Score: 7.5 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor

CVE-2026-87029 / GHSA-55wc-3pg8-jfw6

More information

Details

Impact

undici's decompress interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw. undici's engine converts a synchronous throw from a downstream handler into a per-request failure, but that protection is not in place when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, for example the built-in dump interceptor which throws when a response exceeds its maxSize, escapes as an uncaught exception and terminates the Node.js process.

A malicious or compromised HTTP server can crash any client that composes the decompress interceptor with dump (or another response handler that throws), by returning a small compressed body that decompresses to more than the configured limit. The compressed bytes on the wire are tiny, so only the decompressed size matters. If the application keeps the process alive with a global uncaught-exception handler, the affected request instead hangs until the body timeout.

Patches

Upgrade to undici 7.30.1 or 8.12.2.

Workarounds

Avoid composing the decompress interceptor with a response handler that throws during response processing (such as dump with a maxSize) until upgrading.

Severity

  • CVSS Score: 5.9 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici WebSocket client vulnerable to Denial of Service via unbounded automatic PONG buffering

CVE-2026-109932 / GHSA-9fm3-97px-rjf6

More information

Details

Impact

undici's WebSocket client (including Node.js's bundled globalThis.WebSocket) can be driven to exhaust process memory by a malicious or compromised WebSocket server. For every PING frame received, the receiver automatically writes a PONG response to the socket and ignores the false return value from socket.write(), which is a backpressure signal, so a server that streams small PING frames while never reading the client's PONGs makes the outbound write queue and heap grow without bound until the Node.js process runs out of memory and terminates. The attack is remote and unauthenticated, needs only a normal WebSocket connection, and is asymmetric: small inbound PINGs produce a much larger retained outbound queue. Availability is the only impact. undici 5.x, 6.x, 7.x, and 8.x are affected; the WebSocket client was introduced in 5.15.0.

Patches

Upgrade to 6.29.1, 7.30.1, or 8.12.2, which pause WebSocket frame parsing when the automatic PONG response hits socket backpressure and resume on drain, bounding the outbound queue.

Workarounds

None.

Severity

  • CVSS Score: 5.9 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to Denial of Service via TLS 1.2 certificate-changing renegotiation

CVE-2026-87018 / GHSA-qrxm-fqhp-jwvm

More information

Details

Impact

undici crashes the client process when a TLS 1.2 server renegotiates after the connection is established and presents a different, CA-trusted certificate whose hostname does not match the requested host. Node.js re-runs hostname verification on the renegotiated handshake and destroys the socket with ERR_TLS_CERT_ALTNAME_INVALID. undici's established socket error handler asserted that this error code could never occur, so the peer-controlled error became an uncaught AssertionError that terminates the Node.js process. Both the HTTP/1.1 and HTTP/2 paths are affected.

A malicious or compromised HTTPS endpoint reached through undici or the global fetch() can crash the client with a single server-initiated renegotiation, taking down all in-flight requests and background work in the process. Only TLS 1.2 is affected, because TLS 1.3 does not support renegotiation. Exploitation does not require a CA compromise: the attacker controls the endpoint and can present two ordinary valid certificates, the first matching the requested URL and the second intentionally not matching it.

Patches

Upgrade to undici 6.29.1, 7.30.1, or 8.12.2.

Workarounds

Restrict outbound connections to TLS 1.3, for example by setting connect: { minVersion: 'TLSv1.3', maxVersion: 'TLSv1.3' } on the client or agent, so that renegotiation cannot occur, when the target endpoints support TLS 1.3.

Severity

  • CVSS Score: 7.5 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to TLS certificate validation bypass via dropped tls options in Agent

CVE-2026-109383 / GHSA-2m5v-pch6-74hx

More information

Details

Impact

undici's Agent passes its constructor options through a JSON-based deep clone (JSON.parse(JSON.stringify(...))) before forwarding them to each per-origin Pool. JSON cannot represent functions, so a caller-supplied tls option containing a checkServerIdentity callback is silently dropped before it reaches the TLS layer. As a result, a TLS peer whose certificate a custom checkServerIdentity was written to reject, but which passes Node's default hostname and chain checks, is silently accepted when the request is made through Agent. Because Agent is the default dispatcher behind request, fetch, and setGlobalDispatcher, this is the path most applications use. EnvHttpProxyAgent is also affected on its direct and NO_PROXY routes, which delegate to an internal Agent.

Only applications that pass a function-valued tls option (such as a custom checkServerIdentity for certificate or public-key pinning) are affected. Passing the same options through connect is not affected. This is the Agent counterpart of the BalancedPool certificate validation bypass fixed in CVE-2026-84961.

Patches

Upgrade to undici 6.29.1, 7.30.1, or 8.12.2. Agent now preserves the tls option outside the JSON clone, so custom TLS verification callbacks are forwarded to each origin unchanged.

Workarounds

Pass the TLS options through connect instead of tls. For proxied EnvHttpProxyAgent destinations, use requestTls / proxyTls.

Severity

  • CVSS Score: 7.4 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

undici vulnerable to cache poisoning and cross-user disclosure via cross-origin redirects

CVE-2026-109829 / GHSA-4w7w-5xrc-9h26

More information

Details

Impact

When an originless Agent composes the redirect and cache interceptors as compose(redirect(), cache()) with a shared cache (type: 'shared'), the cache builds its key from the original request URL before the redirect handler changes the origin. The response produced after a redirect is then stored under the original key, even when the redirect crossed to a different origin.

An attacker who controls the target of a redirect from a trusted URL can have their response cached under that trusted URL. A later caller requesting the trusted URL receives the attacker's body from the shared cache without either origin being contacted, allowing persistent cache poisoning. The same key confusion also discloses private data: when an authenticated request returns a private, no-store redirect to a user-specific resource, the final response is stored under the original URL and can be served to a later unauthenticated caller.

The cache interceptor was introduced in undici 7.0.0, and all 7.x and 8.x releases before the patched versions are affected. Applications are affected only when an originless Agent, a shared MemoryCacheStore or SqliteCacheStore, and the composition compose(redirect(), cache()) are all used. Origin-bound Client and Pool dispatchers, and the reverse composition compose(cache(), redirect()), are not affected.

Patches

Upgrade to 7.30.1 or 8.12.2. Before storing a response, undici now verifies that the origin that produced it still matches the cache key, and preserves each redirect hop's cache-control policy, so cross-origin redirect responses and responses behind a no-store or private hop are no longer cached under the original key.

Workarounds

Compose the interceptors as compose(cache(), redirect()), use per-origin dispatchers and cache stores, or disable shared caching on redirect-capable requests.

Severity

  • CVSS Score: 7.4 / 10 (High)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Release Notes

nodejs/undici (undici)

v7.30.1

Compare Source

Security fixes

High severity
Denial of service via TLS 1.2 certificate-changing renegotiation

CVE-2026-87018 · GHSA-qrxm-fqhp-jwvm

A malicious or compromised HTTPS server could crash the Node.js process by initiating TLS 1.2 renegotiation and presenting a different, CA-trusted certificate whose hostname did not match the requested host. The resulting socket error reached an assertion in undici's HTTP/1.1 and HTTP/2 connection handling. This release handles post-connect certificate errors without terminating the process.

TLS certificate validation bypass through dropped Agent options

CVE-2026-109383 · GHSA-2m5v-pch6-74hx

Agent used a JSON-based clone for constructor options, which silently removed function-valued TLS options such as checkServerIdentity. Applications relying on custom certificate or public-key verification could therefore accept a certificate that the callback was intended to reject. This release preserves TLS options when creating per-origin dispatchers.

Cache poisoning and cross-user disclosure through cross-origin redirects

CVE-2026-109829 · GHSA-4w7w-5xrc-9h26

When an originless Agent combined redirect and shared-cache interceptors as compose(redirect(), cache()), a response from a cross-origin redirect could be stored under the original URL. This could allow persistent cache poisoning or disclosure of user-specific responses to later callers. This release verifies the response origin before caching and preserves redirect-hop cache-control policy.

Denial of service through excessive Content-Encoding values

CVE-2026-109869 · GHSA-xjj6-f33q-929c

A malicious HTTP server could crash the Node.js process by returning more than five content codings and closing the connection before sending the body. Although fetch() rejected the response, an error from an orphaned internal stream could remain unhandled. This release validates the content-encoding chain before creating the body stream and aborts oversized chains safely.

Medium severity
Denial of service through the decompress interceptor

CVE-2026-87029 · GHSA-55wc-3pg8-jfw6

An exception thrown by a downstream response handler from an asynchronous decompression callback could escape as an uncaught exception. A server could trigger this when decompress was composed with a handler such as dump with a size limit. This release converts downstream handler exceptions into per-request errors.

Subresource Integrity bypass with non-lowercase algorithm tokens

CVE-2026-109841 · GHSA-f72v-6w45-q472

fetch() treated valid mixed-case or uppercase SRI algorithm tokens, such as SHA256, as unknown and could accept a response whose body did not match the configured digest. This release normalizes algorithm tokens before validation and digest selection.

Denial of service through unbounded EventSource parser state

CVE-2026-109924 · GHSA-4qv8-2p9j-2685

A malicious Server-Sent Events endpoint could exhaust process memory by sending many tiny data: fields without completing an event, or by splitting an unfinished line across many chunks. This release bounds retained EventSource parser state, including field counts, buffered chunks, unfinished-line length, and retained field data.

Denial of service through unbounded automatic WebSocket PONG buffering

CVE-2026-109932 · GHSA-9fm3-97px-rjf6

A malicious WebSocket server could exhaust process memory by flooding the client with PING frames while not reading the automatic PONG responses. undici previously ignored socket backpressure and allowed the outbound queue to grow without bound. This release pauses frame parsing when PONG writes encounter backpressure and resumes after the socket drains.

What's Changed

New Contributors

Full Changelog: nodejs/undici@v7.30.0...v7.30.1

v7.30.0

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What's Changed

Full Changelog: nodejs/undici@v7.29.1...v7.30.0

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@socket-security

socket-security Bot commented Oct 25, 2026 •
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Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff Package Supply Chain
Security		 Vulnerability Quality Maintenance License
Updatedundici@​7.29.1 ⏵ 7.30.193100 +40100 +197100

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@renovate
renovate Bot force-pushed the renovate/npm-undici-vulnerability branch 3 times, most recently from dfe4bb5 to 6d97314 Compare October 30, 2026 16:52
@renovate
renovate Bot force-pushed the renovate/npm-undici-vulnerability branch from 6d97314 to 59fbb9c Compare October 31, 2026 02:46
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