CVE-2026-81267: Stalled popup navigation could allow address bar origin spoofing in Firefox for iOS

Severity: medium (CVSS 5.4 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: 2026-08-31 · updated 2026-09-03
Weakness: CWE-451

Description

A malicious webpage could stall a popup's cross-origin navigation after commit, causing the address bar to display the destination origin while continuing to render attacker-controlled content. This vulnerability was fixed in Firefox for iOS 155.0.

Affected products

Mozilla Firefox for Android: before 155.0 — fixed in 155.0

How to fix

Upgrade to a fixed version: Mozilla Firefox for Android 155.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2052758
https://www.mozilla.org/security/advisories/mfsa2026-81/

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