CVE-2026-4691CRITICAL 9.8EPSS p38.3%

CVE-2026-4691CVE-2026-4691

Description

Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Scoring

CVSS 3.19.8 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS0.49% probability of exploitation · percentile 38.3% · 2026-06-18T12:00:27Z
Published2026-03-24
Last modified2026-04-13

Underlying weaknesses· 1

CWE-416

References

  1. https://bugzilla.mozilla.org/show_bug.cgi?id=2017512
  2. https://www.mozilla.org/security/advisories/mfsa2026-20/
  3. https://www.mozilla.org/security/advisories/mfsa2026-21/
  4. https://www.mozilla.org/security/advisories/mfsa2026-22/
  5. https://www.mozilla.org/security/advisories/mfsa2026-23/
  6. https://www.mozilla.org/security/advisories/mfsa2026-24/

1

TypeTargetConfidenceTier
WeaknessUse After Freecwe-4160%live

Related by meaning· 6

Nearest entities by semantic similarity across the cs-graph corpus.

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.