CVE-2026-109749

5.4Medium

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

5.4Medium

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Impact: Limited impact
Weakness: CWE-416

Impact

Remote attackers can potentially achieve memory corruption or read and modify data in the context of the browser. They need a user to visit a malicious website or open a malicious email containing WebAssembly content.

Root cause

A use-after-free condition exists in the JavaScript WebAssembly component.

Affected systems

Firefox versions prior to 158 and Thunderbird versions prior to 158.

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

Fix & remediation

Upgrade Firefox to version 158 or later, and Thunderbird to version 158 or later. If updating must wait, disable WebAssembly via javascript.options.wasm in about:config.

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

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-109749