Mozilla Firefox prior 153.1/154 GC use after free

Summaryinfo

A vulnerability labeled as critical has been found in Mozilla Firefox. Affected by this issue is some unknown functionality of the component GC. The manipulation results in use after free. This vulnerability is known as CVE-2026-74937. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as critical has been found in Mozilla Firefox. Affected is an unknown part of the component GC. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1.

The advisory is available at bugzilla.mozilla.org. This vulnerability is traded as CVE-2026-74937 since 08/17/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/18/2026).

Upgrading to version 153.1 or 154 eliminates this vulnerability.

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Productinfo

Type

• Web Browser

Vendor

• Mozilla

Name

• Firefox

License

• open-source

Website

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

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