CVE-2025-1012

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.

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-25)

CWE

CWE-416

Published

2025-02-04

Modified

2026-10-05

Record from

the NVD, synced 2026-10-19

Affected

• mozilla:firefox
• mozilla:thunderbird

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1939710
• https://www.mozilla.org/security/advisories/mfsa2025-07/
• https://www.mozilla.org/security/advisories/mfsa2025-08/
• https://www.mozilla.org/security/advisories/mfsa2025-09/
• https://www.mozilla.org/security/advisories/mfsa2025-10/

Check your stackJSON