CVE-2025-5262 Use after free in Thunderbird
A double-free vulnerability in Thunderbird's WebRTC encoder initialization allows attackers to cause memory corruption, potentially leading to code execution or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-5262?
CVE-2025-5262 is a high-severity use after free vulnerability in Mozilla Thunderbird, published on 27 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-415
Which versions are affected by CVE-2025-5262?
It affects 1 product.
Products include Mozilla Thunderbird.
How do I fix CVE-2025-5262?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2025-5262 being exploited?
There is no known exploitation of CVE-2025-5262 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Thunderbird
Sources
Also known as GHSA-v5j6-fjmw-w724, UBUNTU-CVE-2025-5262.