#VU106105 Input validation error in Mozilla Firefox and Firefox ESR - CVE-2025-2857

Vulnerability identifier: #VU106105

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-2025-2857

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

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to insufficient validation of user-supplied input within the IPC code. A remote attacker can trick the victim into visiting a specially crafted website, bypass sandbox restrictions and execute arbitrary code on the system.

Note, the vulnerability is similar to #VU106029 (CVE-2025-2783).

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 100.0 - 136.0.3

Firefox ESR: 102.0 - 102.15.1, 115.5.0 - 115.21.0, 128.0 - 128.8.0

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2025-19/

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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.