CVE-2026-74960

HighCVSS 8.1

Published: 18/08/2026(UTC)Updated: 21/08/2026(UTC)Translated: 19/08/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.17%

7th percentile - higher than 7% of all known CVEs

Summary

Vulnerability in the WebExtensions component related to site isolation. The flaw was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, and Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Risk Assessment

The risk involves potential breach of site isolation, which could lead to unauthorized access to data or actions in the context of another site.

Recommendation

It is recommended to update Firefox or Thunderbird to the patched version as soon as possible.

Original NVD description (English source)

Site isolation issue in the WebExtensions component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.