CVE-2026-109776

4.2Medium

Published 13 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash

4.2Medium

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: Required
Impact: Limited impact
Weakness: CWE-362

Impact

Attackers can potentially read or modify sensitive browser data if they trick a user into visiting a malicious site or opening malicious email content. Exploitation requires victim interaction and precise timing due to high complexity.

Root cause

A race condition exists in the XPCOM component.

Affected systems

Firefox prior to 158, Firefox ESR prior to 153.5, Thunderbird prior to 158, and Thunderbird prior to 153.5.

CVSS v3.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Fix & remediation

Upgrade to Firefox 158, Firefox ESR 153.5, Thunderbird 158, or Thunderbird 153.5. No interim configuration mitigation is available.

shell

$ sudo apt-get update && sudo apt-get install --only-upgrade firefox thunderbird

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD description

Race condition in the XPCOM component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-109776