CVE-2025-27426: Firefox Mobile iOS Full Address Bar Spoof Using Server-Side Redirect to internal error page

Severity: medium (CVSS 5.4 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: none known
Published: 2025-03-04 · updated 2026-06-17
Weakness: CWE-601

Description

Malicious websites utilizing a server-side redirect to an internal error page could result in a spoofed website URL. This vulnerability was fixed in Firefox for iOS 136.

Affected products

Mozilla Firefox: before 136.0 — fixed in 136.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 136.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1933079
https://www.mozilla.org/security/advisories/mfsa2025-13/

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