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CVE-2026-84933GHSA-2JFJ-6HJV-FM6J

undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 7.29.1, 8.10.2
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

undici's cache interceptor does not handle the Set-Cookie response header anywhere in its cache path, so it neither refuses to store nor strips that header. In shared cache mode, which is the default, an otherwise cacheable response that carries a Set-Cookie header, for example one marked with a public and max-age directive, is stored and then re-served to a later caller that matches the same cache key. As a result one caller's cookie is disclosed to a different caller, and an untrusted server can inject cookies into cached responses served to all subsequent callers. This violates the requirement that a shared cache must not store cookies. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • undici undici

    From 7.0.0 · fixed in 7.29.1; From 8.0.0 · fixed in 8.10.2

  • undicinpm

    From 7.0.0 · fixed in 7.29.1

  • undicinpm

    From 8.0.0 · fixed in 8.10.2

References 2

GitHub · nodejs/undici

cna.openjsf.org