Mozilla Firefox up to 138 WebRTC vpx_codec_enc_init_multi memory corruption

Summaryinfo

A vulnerability, which was classified as critical, has been found in Mozilla Firefox up to 138. This affects the function vpx_codec_enc_init_multi of the component WebRTC. The manipulation leads to memory corruption. This vulnerability is uniquely identified as CVE-2025-5262. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Mozilla Firefox up to 138. This issue affects the function vpx_codec_enc_init_multi of the component WebRTC. The manipulation with an unknown input leads to a memory corruption vulnerability. Using CWE to declare the problem leads to CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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 Firefox < 139, Firefox ESR < 115.24, and Firefox ESR < 128.11.

It is possible to read the advisory at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2025-5262 since 05/27/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/20/2025).

The vulnerability scanner Nessus provides a plugin with the ID 237301 (Mozilla Firefox ESR < 115.24), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 139 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (237301) and EUVD (EUVD-2025-25234). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Web Browser

Vendor

• Mozilla

Name

• Firefox

Version

• 138

License

• open-source

Website

• Vendor: https://www.mozilla.org/
• Product: https://www.mozilla.org/en-US/firefox/

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Be aware that VulDB is the high quality source for vulnerability data.

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