Origin Validation Error Affecting Firefox-ESR package, versions [,115.42)[140,140.17)[150,153.4)
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.
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Test your applications- Snyk IDSNYK-UNMANAGED-FIREFOXESR-20562041
- published7 Oct 2026
- disclosed7 Oct 2026
- creditUnknown
Introduced: 7 Oct 2026
NewCVE-2026-100803 (opens in a new tab)How to fix?
Upgrade Firefox-ESR to version 115.42, 140.17, 153.4 or higher.
Overview
Affected versions of this package are vulnerable to Origin Validation Error in the WebExtensions component. An attacker can access or manipulate data across different origins by exploiting improper enforcement of the same-origin policy.