CVE-2026-4687 - Vulnerability Analysis

Overview

Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9 contain a sandbox escape caused by incorrect boundary conditions in the Telemetry component, letting attackers escape sandbox restrictions, exploit requires no special conditions.

Severity & Score

Impact

Attackers can escape sandbox restrictions, potentially leading to full system compromise.

Mitigation

Update to Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9 or later.

References

• https://www.mozilla.org/security/advisories/mfsa2026-20/
• https://www.mozilla.org/security/advisories/mfsa2026-21/
• https://www.mozilla.org/security/advisories/mfsa2026-22/
• https://bugzilla.mozilla.org/show_bug.cgi?id=2016368

Related Resources

• Vulnerability Intelligence Dashboard
• Credential Scanner