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Update dependency undici to v6.24.0 [SECURITY]#183

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renovate/npm-undici-vulnerability
May 20, 2026
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Update dependency undici to v6.24.0 [SECURITY]#183
edelauna merged 1 commit into
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renovate/npm-undici-vulnerability

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@renovate renovate Bot commented May 18, 2026

This PR contains the following updates:

Package Change Age Confidence
undici (source) 6.21.36.24.0 age confidence

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:

  1. Validate header names: Ensure no duplicate Content-Length headers (case-insensitive) are present before passing headers to undici
  2. Use object format: Pass headers as a plain object ({ 'content-length': '123' }) rather than an array, which naturally deduplicates by key
  3. 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: Malicious WebSocket 64-bit length overflows parser and crashes the client

CVE-2026-1528 / GHSA-f269-vfmq-vjvj

More information

Details

Impact

A server can reply with a WebSocket frame using the 64-bit length form and an extremely large length. undici's ByteParser overflows internal math, ends up in an invalid state, and throws a fatal TypeError that terminates the process.

Patches

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

Workarounds

There are no workarounds.

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 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:

  1. Inject arbitrary HTTP headers
  2. 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).


Release Notes

nodejs/undici (undici)

v6.24.0

Compare Source

Undici v6.24.0 Security Release Notes (LTS)

This release backports fixes for security vulnerabilities affecting the v6 line.

Upgrade guidance

All users on v6 should upgrade to v6.24.0 or later.

Fixed advisories

Not applicable to v6

Affected and patched ranges (v6)

References

v6.23.0

Compare Source

Full Changelog: nodejs/undici@v6.22.0...v6.23.0

v6.22.0

Compare Source

What's Changed

Full Changelog: nodejs/undici@v6.21.3...v6.22.0


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@renovate renovate Bot force-pushed the renovate/npm-undici-vulnerability branch from 4ce1e03 to 2eb0f60 Compare May 18, 2026 20:43
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codecov Bot commented May 18, 2026

Codecov Report

✅ All modified and coverable lines are covered by tests.

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@renovate renovate Bot force-pushed the renovate/npm-undici-vulnerability branch 4 times, most recently from d3ba826 to 65f9147 Compare May 19, 2026 22:49
@renovate renovate Bot force-pushed the renovate/npm-undici-vulnerability branch from 65f9147 to 0a29abb Compare May 19, 2026 23:26
@edelauna edelauna merged commit 4b35ab1 into main May 20, 2026
9 checks passed
@edelauna edelauna deleted the renovate/npm-undici-vulnerability branch May 20, 2026 12:17
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