CVE-2021-29974

MEDIUM

Firefox < 90.0 - HSTS Bypass via TLS Error Page Override

Title source: llm
STIX 2.1

Description

When network partitioning was enabled, e.g. as a result of Enhanced Tracking Protection settings, a TLS error page would allow the user to override an error on a domain which had specified HTTP Strict Transport Security (which implies that the error should not be override-able.) This issue did not affect the network connections, and they were correctly upgraded to HTTPS automatically. This vulnerability affects Firefox < 90.

References (3)

Core 3
Core References
Issue Tracking, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1704843
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/202202-03

Scores

CVSS v3 4.3
EPSS 0.0026
EPSS Percentile 48.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Details

Status published
Products (1)
mozilla/firefox < 90.0
Published Aug 05, 2021
Tracked Since Feb 18, 2026