Origin Validation Error 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.
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Test your applications- Snyk IDSNYK-UNMANAGED-FIREFOXESR-16769899
- published20 May 2026
- disclosed19 May 2026
- creditJakub Szymsza
Introduced: 19 May 2026
CVE-2026-8950 (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 Origin Validation Error via the Networking: HTTP component. An attacker can access or manipulate resources across different origins by crafting malicious web requests that exploit improper enforcement of origin checks.