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CVE-2026-14643VulnerabilityPublished

undici vulnerable to cross-user information disclosure via whitespace around equals in Cache-Control directives

Affects undiciSource GCVE Database

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Mentioned vulnerabilities

Not known to be exploited · CVSS 5.9 Medium : upgrade to 7.29.0 when convenient.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 7.29.0, 8.9.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

What to do

Upgrade undici to 7.29.0; undici to 8.9.0.

Affected software

ProductAffectedFixed in
npmundiciAffected
  • >=7.0.0 <7.29.0
Fixed in
  • 7.29.0
npmundiciAffected
  • >=8.0.0 <8.9.0
Fixed in
  • 8.9.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

## Impact Undici's cache interceptor mishandles optional whitespace (OWS) placed around the `=` of a qualified `no-cache` or `private` Cache-Control directive, such as `no-cache ="authorization"` (OWS before `=`) or `no-cache= "authorization"` (OWS after `=`). The parser either drops the directive entirely or stores a field name with literal quote characters, so the downstream cache decisions do not recognize the qualification and the response is stored. In shared-cache mode, this allows a response containing one user's authenticated data to be served from cache to a subsequent caller, including an unauthenticated caller, when both requests resolve to the same cache key. The impact class is identical to CVE-2026-9678 (GHSA-pr7r-676h-xcf6); this advisory covers the whitespace-around-`=` bypass that the earlier fix did not normalize. Affected applications are those that explicitly enable the cache interceptor (`interceptors.cache()`) in shared mode, forward `Authorization` headers upstream, and receive cacheable responses with qualified `private` or `no-cache` directives whose field-name list is padded with OWS around the `=`. ## Patches Upgrade to undici v7.29.0 or v8.9.0. ## Workarounds If upgrade is not immediately possible, disable shared-cache mode for traffic that includes `Authorization` headers, avoid caching responses to authenticated requests, or add `Vary: Authorization` upstream.

References

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