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CVE-2026-100788

Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

Scores

9.8
CVSS 9.8 out of 10, critical severity.
0.4%
EPSS 0.4% chance of exploitation in the next 30 days.

The facts

Published
29 September 2026
Last changed
1 October 2026
NVD status
Undergoing Analysis
Severity
Critical, CVSS 9.8 out of 10 (version 3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
Known exploited
Not in the CISA Known Exploited Vulnerabilities catalogue in this build.
EPSS
0.4% chance of exploitation activity in the next 30 days (percentile 37).

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References