Use After Free Affecting Firefox-ESR package, versions [,115.34.0)[116.0.0,140.9.0)
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-15762917
- published24 Mar 2026
- disclosed24 Mar 2026
- creditFabius Artrel
Introduced: 24 Mar 2026
CVE-2026-4691 (opens in a new tab)How to fix?
Upgrade Firefox-ESR to version 115.34.0, 140.9.0 or higher.
Overview
Affected versions of this package are vulnerable to Use After Free through the CSS Parsing and Computation process. An attacker can execute arbitrary code or cause a denial of service by triggering a use-after-free condition during CSS processing.