CVE-2025-1020CRITICAL 9.8EPSS p39.0%

CVE-2025-1020CVE-2025-1020

Description

Memory safety bugs present in Firefox 134 and Thunderbird 134. 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 135 and Thunderbird 135.

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
EPSS0.50% probability of exploitation · percentile 39.0% · 2026-06-18T12:00:27Z
Published2025-02-04
Last modified2026-04-13

Underlying weaknesses· 1

CWE-787

References

  1. https://bugzilla.mozilla.org/buglist.cgi?bug_id=1939063%2C1942169
  2. https://www.mozilla.org/security/advisories/mfsa2025-07/
  3. https://www.mozilla.org/security/advisories/mfsa2025-11/

1

TypeTargetConfidenceTier
WeaknessOut-of-bounds Writecwe-7870%live

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