Remote code execution in Mozilla Firefox and Firefox ESR

1) Input validation error

EUVDB-ID: #VU106105

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 - Improper input validation

Exploit availability: No

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 - 128.8.0

CPE2.3

• cpe:2.3:a:mozilla:mozilla_firefox:100.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:100.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:100.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:102.15.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:115.21.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:128.8.0:*:*:*:*:*:*:*

External links

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

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

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