CVE-2026-84933undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches
Updated under an hour ago ()
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It affects undici and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
- Weakness (CWE)
- CWE-200, CWE-524
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- openjs
- NVD analysis
- Analyzed
- Record last updated
- Sep 4, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
undici undici undici:undici (from the name) | from 7.0.0 before 7.29.1; 7.29.1 not affected; from 8.0.0 before 8.10.2; 8.10.2 not affected | CNA record |
nodejs undici nodejs:undici | from 7.0.0 before 7.29.1; from 8.0.0 before 8.10.2 | NVD |
References
- https://github.com/nodejs/undici/security/advisories/GHSA-2jfj-6hjv-fm6jvendor-advisory
- https://cna.openjsf.org/security-advisories.htmlthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.