CVE-2026-103418 Universal XSS via the HTML language attribute in Translation Services
Attacker-controlled HTML language attributes in Firefox for iOS allow universal XSS, enabling code execution in privileged contexts and bypassing Content Security Policy.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-103418?
CVE-2026-103418 is a high-severity cross-site scripting vulnerability in Mozilla Firefox for iOS, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Firefox for iOS directly interpolated the page’s HTML language attribute into translation JavaScript, allowing attacker-controlled markup to execute code in Firefox’s privileged content world and bypass the page’s Content Security Policy. This vulnerability was fixed in Firefox for iOS 157.1.
Weakness: CWE-79
Which versions are affected by CVE-2026-103418?
How do I fix CVE-2026-103418?
No fix has been published for CVE-2026-103418 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-103418 being exploited?
There is no known exploitation of CVE-2026-103418 in the wild and no public exploit code.
Sources
Also known as GHSA-7fw9-g4rg-xvqv.