CVE-2025-23109: Address bar spoofing on iOS using long hostnames

Severity: medium (CVSS 6.5 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: 2025-01-11 · updated 2026-10-05
Weakness: CWE-346

Description

Long hostnames in URLs could be leveraged to obscure the actual host of the website or spoof the website address. This vulnerability was fixed in Firefox for iOS 134.

Affected products

Mozilla Firefox: before 134.0 — fixed in 134.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 134.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1419275
https://www.mozilla.org/security/advisories/mfsa2025-06/

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