CVE-2025-6431: firefox Access Control Flaw — Fix

Description

When a link can be opened in an external application, Firefox for Android will, by default, prompt the user before doing so. An attacker could have bypassed this prompt, potentially exposing the user to security vulnerabilities or privacy leaks in external applications. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Weakness Type (CWE)

CWE-285 CWE-285

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 140.0
google	android	All

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-51/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1942716

Frequently Asked Questions

What is CVE-2025-6431? +

When a link can be opened in an external application, Firefox for Android will, by default, prompt the user before doing so. An attacker could have bypassed this prompt, potentially exposing the user to security vulnerabilities or privacy leaks in external applications. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2025-6431? +

CVE-2025-6431 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-6431? +

CVE-2025-6431 affects products from google, mozilla, specifically: android, firefox. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-6431? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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