Mozilla Firefox up to 135 on 64-bit JIT return value

Summaryinfo

A vulnerability was found in Mozilla Firefox up to 135 on 64-bit. It has been declared as problematic. Affected is an unknown function of the component JIT. Executing a manipulation can lead to return value. This vulnerability appears as CVE-2025-1933. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mozilla Firefox up to 135 on 64-bit. It has been declared as problematic. This vulnerability affects some unknown processing of the component JIT. The manipulation with an unknown input leads to a return value vulnerability. The CWE definition for the vulnerability is CWE-252. The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions. As an impact it is known to affect confidentiality. CVE summarizes:

On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

The advisory is shared for download at bugzilla.mozilla.org. This vulnerability was named CVE-2025-1933 since 03/04/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 04/15/2026).

The vulnerability scanner Nessus provides a plugin with the ID 232196 (SUSE SLED15 / SLES15 / openSUSE 15 Security Update : MozillaFirefox (SUSE-SU-2025:0788-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 136 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (232196). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Web Browser

Vendor

• Mozilla

Name

• Firefox

Version

• 135

License

• open-source

Website

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

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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