CVE-2026-16387

CriticalCVSS 9.8

Published: 21/07/2026(UTC)Updated: 24/07/2026(UTC)Translated: 24/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.22%

12th percentile - higher than 12% of all known CVEs

Summary

Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Risk Assessment

Site isolation breach could allow an attacker to read data from other sites, compromising confidentiality.

Recommendation

Update Firefox to version 153 or later, and Thunderbird to version 153 or later.

Original NVD description (English source)

Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.