Quick answers
- Is CVE-2026-103417 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-103417 being exploited in the wild.
- How severe is CVE-2026-103417?
- Medium severity, with a CVSS score of 5.5, published 13 October 2026.
- Which products and versions are affected?
- Mozilla Firefox for iOS before 157.1.
- Is there a fix for CVE-2026-103417?
- Yes: fixed in Firefox for iOS 157.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-103417 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-103417?
- Check whether you run Mozilla Firefox for iOS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: Firefox for iOS 157.1
Technical details
The vulnerability occurs in Firefox for iOS's saved-login autofill mechanism, which failed to validate that the target page's origin matched the page where credentials were originally requested. If a cross-origin navigation occurred while the saved-login UI was open, autofill would proceed on the new page without origin verification. An attacker can exploit this via a page that triggers credential selection and then navigates to a malicious site, causing the victim's credentials to be filled and submitted to the attacker's domain.
Affected products
- Mozilla Firefox for iOS before 157.1
Timeline
- 2026-10-05: disclosed
- 2026-10-05: patched