Mozilla Firefox up to 139 Multi-Account Container information disclosure

Summaryinfo

A vulnerability was found in Mozilla Firefox up to 139. It has been classified as problematic. The affected element is an unknown function of the component Multi-Account Container Handler. This manipulation causes information disclosure. The identification of this vulnerability is CVE-2025-6432. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic was found in Mozilla Firefox up to 139. Affected by this vulnerability is an unknown code block of the component Multi-Account Container Handler. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. The summary by CVE is:

When Multi-Account Containers was enabled, DNS requests could have bypassed a SOCKS proxy when the domain name was invalid or the SOCKS proxy was not responding. This vulnerability affects Firefox < 140.

It is possible to read the advisory at bugzilla.mozilla.org. This vulnerability is known as CVE-2025-6432 since 06/20/2025. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/17/2025). The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 242306 (SUSE SLES12 Security Update : MozillaFirefox, MozillaFirefox-branding-SLE (SUSE-SU-2025:02339-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 140 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (242306), EUVD (EUVD-2025-21376) and CERT Bund (WID-SEC-2025-1850). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Xerox FreeFlow Print Server

Productinfo

Type

• Web Browser

Vendor

• Mozilla

Name

• Firefox

Version

• 139

License

• open-source

Website

• Vendor: https://www.mozilla.org/
• Product: https://www.mozilla.org/en-US/firefox/

CPE 2.3info

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CPE 2.2info

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