CVE-2026-84933

highpriority · track · 33EPSS 0.003 · 22 %ileDEFRUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.30% (22nd) EPSS
CVSS 8.2 · high
Is it mine?
9 products
Check your exposure
Who says so?
4 sources
cert_bund · nvd · osv · certfr

EPSS · scored 2026-10-22

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

8.2
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–8.2

v3.18.2highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 4.2
v3.16.5mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:Nsecondaryexploitability 2.2 · impact 4.2
v3.16.5mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:Nsecondary · OSV
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

04

affected products (9)

Products and version ranges known to be affected.

05

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-3596IBM App Connect Enterprise: Mehrere SchwachstellenDeutsch2026-09-27csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren und um einen Cross-Site Scripting Angriff durchzuführen.

  • GHSA-2jfj-6hjv-fm6jundici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches2026-09-29ghsa · osvUS

    ### Impact undici's `interceptors.cache()` does not handle `Set-Cookie` in the cache path. In shared-cache mode (`type: 'shared'`, the default), a cacheable response (for example `Cache-Control: public, max-age=...`) carrying a `Set-Cookie` header is stored, and the stored `Set-Cookie` is re-served to a later caller that hits the same cache key. This exposes one user's cookie to another caller and lets an untrusted upstream inject cookies into cached responses served to all subsequent callers, violating RFC 6265 section 7.2 (a shared cache must not store cookies). Applications using the shared cache interceptor against untrusted or multi-user upstreams are affected. Private caches (`type: 'private'`) are not affected. ### Patches Upgrade to `7.29.1` or `8.10.2`. In shared-cache mode, undici no longer stores or re-serves responses containing `Set-Cookie`, including previously cached entries and revalidation paths. ### Workarounds Use a private cache (`type: 'private'`) for per-user responses, or avoid caching responses that set cookies. Applications acting as shared caches should strip `Set-Cookie` from responses before caching.

  • CERTFR-2026-AVI-1336Multiples vulnérabilités dans les produits IBMFrançais2026-10-16vendor · certfrFR
  • CERTFR-2026-AVI-1378Multiples vulnérabilités dans les produits IBMFrançais2026-10-23vendor · certfrFR
06

sources

Which sources assert this record, and when.

published 2026-09-04modified 2026-09-15
07

references (2) nvd

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan