CVE-2026-103418 Firefox for iOS - Stored XSS

Firefox for iOS < 157.1 contains a stored XSS caused by direct interpolation of the page's HTML language attribute into translation JavaScript, letting attackers execute code in privileged content and bypass CSP, exploit requires attacker-controlled markup.

CVSS base score 8.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.30% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Stored XSS
Impact
Client Script Exec
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
13 October 2026
Updated
15 October 2026
Weakness
CWE-79

Vendor fix

Update to Firefox for iOS 157.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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