CVE-2026-100796

HighCVSS 8.8

Published: 29/09/2026(UTC)Updated: 30/09/2026(UTC)Translated: 01/10/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.30%

21th percentile - higher than 21% of all known CVEs

Summary

Use-after-free vulnerability in the JavaScript: WebAssembly component. Fixed in Thunderbird 157 and Firefox 157.

Risk Assessment

Use-after-free could lead to crashes or potential code execution, which could be exploited to attack the system.

Recommendation

Update Firefox or Thunderbird to version 157 or later.

Other vulnerabilities in Firefox

See all

CVE-2026-109778High
A privilege escalation vulnerability in the WebExtensions component. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
CVE-2026-109756High
A privilege escalation vulnerability in the DOM: Navigation component. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
CVE-2026-109709High
An information disclosure and privilege escalation vulnerability in the Security: Process Sandboxing component. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
CVE-2026-109707Critical
Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
CVE-2026-109705Critical
Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
CVE-2026-106016Critical
Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 157.0.1 and Thunderbird 158.
CVE-2026-100829Critical
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
CVE-2026-100828Critical
Mitigation bypass in the Bookmarks & History component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
CVE-2026-100819Critical
Sandbox escape due to incorrect boundary conditions in the XPCOM component. Fixed in multiple Firefox and Thunderbird versions.
CVE-2026-100818Critical
Sandbox escape due to use-after-free in the Widget: Gtk component. Fixed in multiple Firefox and Thunderbird versions.

Original NVD description (English source)

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS