CVE-2025-5262

HIGH 7.5CVE-2025-5262 · Published 27/05/2025 · updated 17/06/2026

In short

CVE-2025-5262 is a HIGH (CVSS 7.5) vulnerability affecting thunderbird (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.46%, higher than 40.3% of all vulnerabilities.
Fix: update to 128.11.0, 139.0 or later.

Package	Affected versions	Patched versions
thunderbird mozilla	`< 128.11.0< 139.0`	`128.11.0139.0`

Description

A double-free could have occurred in `vpx_codec_enc_init_multi` after a failed allocation when initializing the encoder for WebRTC. This could have caused memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 139 and Thunderbird < 128.11.

References

bugzilla.mozilla.org/show_bug.cgi · Issue Tracking
mozilla.org/security/advisories/mfsa2025-45 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-46 · Vendor Advisory

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Package

Affected versions

Patched versions

thunderbird

mozilla

< 128.11.0< 139.0

128.11.0139.0

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