Update dependency undici to v6 [SECURITY] by renovate[bot] · Pull Request #88 · tidbcloud/serverless-js

renovate · 2026-03-26T18:32:49Z

ℹ️ Note

This PR body was truncated due to platform limits.

This PR contains the following updates:

Package	Change	Age	Confidence
undici (source)	`^5.26.2` → `^6.0.0`

Undici has an HTTP Request/Response Smuggling issue

CVE-2026-1525 / GHSA-2mjp-6q6p-2qxm

More information

Details

Impact

Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire.

Who is impacted:

Applications using undici.request(), undici.Client, or similar low-level APIs with headers passed as flat arrays
Applications that accept user-controlled header names without case-normalization

Potential consequences:

Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate Content-Length headers (400 Bad Request)
HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking

Patches

Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.

Workarounds

If upgrading is not immediately possible:

Validate header names: Ensure no duplicate Content-Length headers (case-insensitive) are present before passing headers to undici
Use object format: Pass headers as a plain object ({ 'content-length': '123' }) rather than an array, which naturally deduplicates by key
Sanitize user input: If headers originate from user input, normalize header names to lowercase and reject duplicates

Severity

CVSS Score: 6.5 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

References

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

Undici has CRLF Injection in undici via `upgrade` option

CVE-2026-1527 / GHSA-4992-7rv2-5pvq

More information

Details

Impact

When an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to:

Inject arbitrary HTTP headers
Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch)

The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters:

// lib/dispatcher/client-h1.js:1121
if (upgrade) {
  header += `connection: upgrade\r\nupgrade: ${upgrade}\r\n`
}

Patches

Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.

Workarounds

Sanitize the upgrade option string before passing to undici:

function sanitizeUpgrade(value) {
  if (/[\r\n]/.test(value)) {
    throw new Error('Invalid upgrade value')
  }
  return value
}

client.request({
  upgrade: sanitizeUpgrade(userInput)
})

Severity

CVSS Score: 4.6 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:L/PR:L/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 HTTP response queue poisoning via keep-alive socket reuse

CVE-2026-6733 / GHSA-35p6-xmwp-9g52

More information

Details

Impact

Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.

This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

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 HTTP header injection via Set-Cookie percent-decoding

CVE-2026-9679 / GHSA-p88m-4jfj-68fv

More information

Details

Impact

undici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equivalents. RFC 6265 §5.4 does not specify any decoding and browsers do not decode either.

Applications that parse a Set-Cookie header and then forward the parsed value into a response header (proxies, middleware, SSR frameworks) become vulnerable to HTTP response header injection: an attacker-controlled upstream can inject arbitrary Set-Cookie, Location, or Cache-Control headers into the application's downstream response, enabling session fixation, open redirect, or cache poisoning.

Affected applications are those that use undici's cookie parsing (parseSetCookie, parseCookie, getSetCookies) and forward the parsed cookie value into a response header.

This was introduced in undici 7.0.0 via #3789.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

If upgrade is not immediately possible, do not forward values returned by parseSetCookie/parseCookie/getSetCookies directly into response headers; sanitize the value first to strip or reject CR, LF, NUL, ;, and = bytes.

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 Set-Cookie SameSite attribute downgrade via permissive substring matching

CVE-2026-11525 / GHSA-g8m3-5g58-fq7m

More information

Details

Impact

When undici parses a Set-Cookie header, it accepts any SameSite attribute value that contains Strict, Lax, or None as a substring, rather than the case-insensitive exact match specified by RFC 6265. Non-spec values are silently mapped to one of the three standard tokens:

SameSite=NoneOfYourBusiness is parsed as None, the most permissive setting.
SameSite=StrictLax is parsed as Lax, a downgrade from Strict.

Affected applications are those that consume Set-Cookie headers from server responses (for example via undici's fetch or proxy code paths) and then forward or rely on the parsed sameSite attribute. A malicious or non-compliant server can coerce the consumer's view of a cookie's SameSite policy to a weaker value, silently degrading the SameSite enforcement the cookie is supposed to provide.

This was introduced in undici 5.15.0 when the cookies feature was added.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

After parsing a Set-Cookie header, validate that the resulting sameSite attribute is one of 'Strict', 'Lax', or 'None' (exact, case-insensitive) before forwarding or relying on it.

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).

Release Notes

nodejs/undici (undici)

Advisory	CVE	Severity (CVSS)	Fixed in	Fix commit
GHSA-vxpw-j846-p89q	CVE-2026-12151	High (7.5)	6.27.0	`b7f252e7`
GHSA-p88m-4jfj-68fv	CVE-2026-9679	Moderate (5.9)	6.27.0	`25efa447`
GHSA-g8m3-5g58-fq7m	CVE-2026-11525	Low (3.7)	6.27.0	`25efa447`
GHSA-35p6-xmwp-9g52	CVE-2026-6733	Low (3.7)	6.27.0	`f4c31d60`

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renovate Bot commented Mar 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Undici has an HTTP Request/Response Smuggling issue

Details

Impact

Patches

Workarounds

Severity

References

Undici has CRLF Injection in undici via upgrade option

Details

Impact

Patches

Workarounds

Severity

References

undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

Details

Impact

Patches

Workarounds

Severity

References

undici vulnerable to HTTP header injection via Set-Cookie percent-decoding

Details

Impact

Patches

Workarounds

Severity

References

undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching

Details

Impact

Patches

Workarounds

Severity

References

Release Notes

⚠️ Security Release

Summary

High severity

WebSocket DoS via fragment count bypass — CVE-2026-12151

Moderate severity

HTTP header injection via Set-Cookie percent-decoding — CVE-2026-9679

Low severity

Set-Cookie SameSite attribute downgrade — CVE-2026-11525

HTTP response queue poisoning via keep-alive socket reuse — CVE-2026-6733

Release contents & deliberate backports

Credits

What's Changed

What's Changed

Undici v6.24.0 Security Release Notes (LTS)

Upgrade guidance

Fixed advisories

Not applicable to v6

Affected and patched ranges (v6)

References

⚠️ Security Release

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renovate Bot commented Mar 26, 2026 •

edited

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Undici has CRLF Injection in undici via `upgrade` option