CVE-2026-0891HIGH 8.1EPSS p30.6%

CVE-2026-0891CVE-2026-0891

Description

Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Scoring

CVSS 3.18.1 (HIGH)
VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS0.39% probability of exploitation · percentile 30.6% · 2026-06-19T12:03:05Z
Published2026-01-13
Last modified2026-04-13

Underlying weaknesses· 1

CWE-119

References

  1. https://bugzilla.mozilla.org/buglist.cgi?bug_id=1964722%2C2000981%2C2003100%2C2003278
  2. https://www.mozilla.org/security/advisories/mfsa2026-01/
  3. https://www.mozilla.org/security/advisories/mfsa2026-03/
  4. https://www.mozilla.org/security/advisories/mfsa2026-04/
  5. https://www.mozilla.org/security/advisories/mfsa2026-05/

1

TypeTargetConfidenceTier
WeaknessImproper Restriction of Operations within the Bounds of a Memory Buffercwe-1190%live

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