Origin Validation Error Affecting Firefox-ESR package, versions [,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-20826639
- published11 Oct 2026
- disclosed11 Oct 2026
- creditUnknown
Introduced: 11 Oct 2026
NewCVE-2026-100809 (opens in a new tab)How to fix?
Upgrade Firefox-ESR to version 153.4 or higher.
Overview
Affected versions of this package are vulnerable to Origin Validation Error via the DevTools component. An attacker can access cross-origin resources by exploiting improper enforcement of origin restrictions.