User Impersonation Affecting Firefox-ESR package, versions [,140.11)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-UNMANAGED-FIREFOXESR-16769919
- published20 May 2026
- disclosed19 May 2026
- creditHafiizh
Introduced: 19 May 2026
CVE-2026-8961 (opens in a new tab)How to fix?
Upgrade Firefox-ESR to version 140.11 or higher.
Overview
Affected versions of this package are vulnerable to User Impersonation via the Form Autofill process. An attacker can deceive users into entering sensitive information into malicious forms by presenting spoofed autofill suggestions.