What is CVE-2025-5262?

CVE-2025-5262 is a high-severity vulnerability in Mozilla Thunderbird, classified under Double Free. CVSS score: 7.5/10. Published 2025-05-27.

How severe is CVE-2025-5262?

High severity. CVSS v3 base score is 7.5 out of 10.

Double Free in Mozilla Thunderbird

CVE-2025-5262

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.

Vulnerability class: Double Free

EPSS: 0.004 (32.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mozilla Thunderbird — versions unspecified

Weakness classification (CWE)

CWE-415 — Double Free

References

security@mozilla.org (Permissions Required, Issue Tracking)
security@mozilla.org (Vendor Advisory)
security@mozilla.org (Vendor Advisory)

Frequently asked questions

What is CVE-2025-5262?: CVE-2025-5262 is a high-severity vulnerability in Mozilla Thunderbird, classified under Double Free. CVSS score: 7.5/10. Published 2025-05-27.
How severe is CVE-2025-5262?: High severity. CVSS v3 base score is 7.5 out of 10.