Signed to Unsigned Conversion 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-16761527
- published20 May 2026
- disclosed19 May 2026
- creditYaqoub Aldurayhim
Introduced: 19 May 2026
CVE-2026-8958 (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 Signed to Unsigned Conversion Error via the Process Sandboxing component. An attacker can access sensitive information or escape the intended process isolation by exploiting weaknesses in the sandbox implementation.