#VU105318 Input validation error in Mozilla products - CVE-2025-1936

Vulnerability identifier: #VU105318

Vulnerability risk: Low

CVSSv4.0: 0.5 [CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-1936

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers
Firefox for Android
Mobile applications / Apps for mobile phones

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to bypass security restrictions.

The vulnerability exists due to insufficient validation of a null-byte character (e.g. %00) in the filename when retrieving local file content packaged in a ZIP archive via jar: URLs. The null and everything after it is ignored when retrieving the content from the archive, but the fake extension after the null is used to determine the type of content. A remote attacker can hide code in a web extension disguised as a safe file, such as an image.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 128.0 - 135.0.1

Firefox ESR: 128.0 - 128.7.0

Firefox for Android: 128.0 - 135.0.1

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External links
https://bugzilla.mozilla.org/show_bug.cgi?id=1940027
https://www.mozilla.org/security/advisories/mfsa2025-14/
https://www.mozilla.org/security/advisories/mfsa2025-16/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.