Cyber Posture

CVE-2025-1012

High

Published: 04 February 2025

Published
04 February 2025
Modified
13 April 2026
KEV Added
Patch
CVSS Score 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0043 62.4th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Description

A race during concurrent delazification could have led to a use-after-free. This vulnerability was fixed in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

Security Summary

CVE-2025-1012 is a use-after-free vulnerability (CWE-416) caused by a race condition during concurrent delazification in Mozilla Firefox and Thunderbird. The flaw affects versions of Firefox prior to 135, Firefox ESR prior to 115.20 and 128.7, Thunderbird prior to 128.7 and 135. It was publicly disclosed on 2025-02-04 and carries a CVSS v3.1 base score of 7.5.

The vulnerability can be exploited remotely over the network (AV:N) by attackers requiring no privileges (PR:N), though exploitation demands high complexity (AC:H) and user interaction (UI:R), with no change in scope (S:U). Successful attacks could achieve high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), potentially enabling arbitrary code execution or memory corruption in the browser context.

Mozilla's security advisories (MFSA2025-07, MFSA2025-08, MFSA2025-09, and MFSA2025-10), along with Bugzilla entry 1939710, confirm the issue was addressed in the specified fixed releases. Mitigation involves updating affected Firefox and Thunderbird installations to the patched versions as soon as possible.

Details

CWE(s)
CWE-416

Affected Products

mozilla
firefox
≤ 115.20.0 · ≤ 135.0 · 128.1.0 — 128.7.0
mozilla
thunderbird
≤ 135.0 · 128.0.1 — 128.7.0

References