CVE-2026-84933

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 84% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — Patch released this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

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 v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
16%
KEV
Not listed

Published

September 4, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Sep 4, 2026
Patch available. Sources: github.
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html
github Patch Available

undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches · Advisory · nodejs/undici · GitHub

https://github.com/nodejs/undici/security/advisories/GHSA-2jfj-6hjv-fm6j

Vendor Advisories for CVE-2026-84933(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatgrafana12-4-main-12.4.10-0.2.hum12026-09-09redhat
redhatnodejs26-main-26.7.0-1.5.2.hum12026-08-12redhat
redhatnodejs24-main-24.18.1-0.2.2.hum12026-08-12redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
node-undici5.15.0+dfsg1+~cs20.10.9.3-1 ... 8.9.0+dfsg+~cs3.2.0-1 (39 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 21× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-11 14:53 UTCEPSS rescore
  3. 2026-09-10 23:50 UTCEG score recompute
  4. 2026-09-10 23:50 UTCVendor advisory
  5. 2026-09-09 23:22 UTCEG score recompute
  6. 2026-09-09 23:22 UTCVendor advisory
  7. 2026-09-08 22:01 UTCEPSS rescore
  8. 2026-09-08 19:56 UTCVendor advisory
  9. 2026-09-07 19:42 UTCEG score recompute
  10. 2026-09-07 19:42 UTCVendor advisory
  11. 2026-09-06 19:35 UTCEG score recompute
  12. 2026-09-06 19:35 UTCVendor advisory
  13. 2026-09-06 13:48 UTCEPSS rescore
  14. 2026-09-05 19:26 UTCEG score recompute
  15. 2026-09-05 19:26 UTCVendor advisory
  16. 2026-09-05 15:31 UTCEPSS rescore
  17. 2026-09-04 19:19 UTCEG score recompute
  18. 2026-09-04 18:39 UTCEG score recompute
  19. 2026-09-04 17:25 UTCEG score recompute
  20. 2026-09-04 17:05 UTCEG score recompute
  21. 2026-09-04 17:04 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-84933?
CVE-2026-84933 is a medium vulnerability published on September 4, 2026. 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…
When was CVE-2026-84933 disclosed?
CVE-2026-84933 was first published in the National Vulnerability Database on September 4, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-84933 actively exploited?
CVE-2026-84933 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 84.1% of all scored CVEs.
What is the CVSS score of CVE-2026-84933?
CVE-2026-84933 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-84933?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-84933, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-84933

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