Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-84933

CVE-2026-84933HIGH

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

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  L  N    8.2   .0030   20.9     —

AFFECTED
  Product  Versions  Fixed
  undici   7.0.0 –   7.29.1

TIMELINE
  Sep 2   Reserved by openjs
  Sep 4   Published (CNA: openjs)
  Sep 15  RESCORED — CVE-2026-84933 (undici). CVSS 6.5 → 8.2 (NVD).

CWE-200, CWE-524 · CNA: openjs · CVSS v3.1 · 2 references · NVD status: Analyzed

Description

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
September 2, 2026	Reserved	Reserved by openjs
September 4, 2026	Published	Published (CNA: openjs)
September 15, 2026	RESCORED	RESCORED — CVE-2026-84933 (undici). CVSS 6.5 → 8.2 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
undici	undici	—	7.0.0	7.29.1

Weaknesses

CWE-200 · CWE-524

References (2)

https://cna.openjsf.org/security-advisories.html [Third Party Advisory]
https://github.com/nodejs/undici/security/advisories/GHSA-2jfj-6hjv-fm6j [Vendor Advisory]

Authoritative record: CVE-2026-84933 at cve.org

Vendors: undici

Weaknesses: CWE-200 · CWE-524

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-84933 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.