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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-84933
StatePUBLISHED
Assigneropenjs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-04 17:17:01 UTC
Updated2026-09-08 19:07:52 UTC
Descriptionundici'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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from ce714d77-add3-4f53-aff5-83d477b104bb

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

EPSS: 0.002460000 probability, percentile 0.158260000 (date 2026-09-08)

Problem Types: CWE-200 | CWE-524 | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor | CWE-524 CWE-524: Use of Cache Containing Sensitive Information

VersionSourceTypeScoreSeverityVector
3.1ce714d77-add3-4f53-aff5-83d477b104bbSecondary6.5MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
3.1CNACVSS6.5MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Undici Undici affected 7.0.0 7.29.1 semver Not specified
CNA Undici Undici unaffected 7.29.1 semver Not specified
CNA Undici Undici affected 8.0.0 8.10.2 semver Not specified
CNA Undici Undici unaffected 8.10.2 semver Not specified

References

ReferenceSourceLinkTags
cna.openjsf.org/security-advisories.html ce714d77-add3-4f53-aff5-83d477b104bb cna.openjsf.org
github.com/nodejs/undici/security/advisories/GHSA-2jfj-6hjv-fm6j ce714d77-add3-4f53-aff5-83d477b104bb github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: mcollina (en)

CNA: UlisesGascon (en)

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