CVE-2026-4700

critical

Description

Mitigation bypass in the Networking: HTTP component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

References

https://www.mozilla.org/security/advisories/mfsa2026-24/

https://www.mozilla.org/security/advisories/mfsa2026-23/

https://www.mozilla.org/security/advisories/mfsa2026-22/

https://www.mozilla.org/security/advisories/mfsa2026-20/

https://bugzilla.mozilla.org/show_bug.cgi?id=2003766

Details

Source: Mitre, NVD

Published: 2026-03-24

Updated: 2026-03-24

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H