CVE-2025-6428: Firefox for Android opened URLs specified in a link querystring parameter

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-06-24 · updated 2026-09-30
Weakness: CWE-601

Description

When a URL was provided in a link querystring parameter, Firefox for Android would follow that URL instead of the correct URL, potentially leading to phishing attacks. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140.

Affected products

Mozilla Firefox: before 140.0 — fixed in 140.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 140.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1970151
https://www.mozilla.org/security/advisories/mfsa2025-51/

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