#VU109875 Information disclosure in Mozilla products - CVE-2025-5266

Vulnerability identifier: #VU109875

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-5266

CWE-ID: CWE-200

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 gain access to potentially sensitive information.

The vulnerability exists due to script elements loading cross-origin resources generated load and error events, which leaked information. A remote attacker can gain access to sensitive information.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 120.0 - 138.0.4

Firefox ESR: 128.0, 128.1.0, 128.2.0, 128.3.0, 128.3.1, 128.4.0, 128.5.0, 128.5.1, 128.5.2, 128.6.0, 128.7.0, 128.8.0, 128.8.1, 128.9.0, 128.10.0, 128.10.1

Firefox for Android: 120.0 - 138.0

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External links
https://bugzilla.mozilla.org/show_bug.cgi?id=1965628
https://www.mozilla.org/security/advisories/mfsa2025-42/
https://www.mozilla.org/security/advisories/mfsa2025-44/

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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.