TLS Error Page Override Vulnerability in Firefox < 90

CVE-2021-29974 · MEDIUM Severity

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

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.

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