CVE-2025-11720: Spoofing risk in Android custom tabs

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-14 · updated 2026-10-08
Weakness: CWE-451

Description

The Firefox and Firefox Focus UI for the Android custom tab feature only showed the "site" that was loaded, not the full hostname. User supplied content hosted on a subdomain of a site could have been used to fool a user into thinking it was content from a different subdomain of that site. This vulnerability was fixed in Firefox 144.

Affected products

Mozilla Firefox: before 144.0 — fixed in 144.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 144.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1979534
https://bugzilla.mozilla.org/show_bug.cgi?id=1984370
https://www.mozilla.org/security/advisories/mfsa2025-81/

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