#VU105302 Use-after-free in Firefox ESR and Mozilla Firefox - CVE-2025-1931

Vulnerability identifier: #VU105302

Vulnerability risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2025-1931

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Firefox ESR
Client/Desktop applications / Web browsers
Mozilla Firefox
Client/Desktop applications / Web browsers

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in WebTransportChild. A remote attacker can trick the victim into visiting a specially crafted website, trigger a use-after-free in the content process side of a WebTransport connection and execute arbitrary code on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Firefox ESR: 115.0 - 115.20.0, 128.0 - 128.7.0

Mozilla Firefox: 100.0 - 135.0.1

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External links
https://bugzilla.mozilla.org/show_bug.cgi?id=1944126
https://www.mozilla.org/security/advisories/mfsa2025-14/
https://www.mozilla.org/security/advisories/mfsa2025-15/
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.