CVE-2021-29974
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…
Does this matter?
Lower severity and a low EPSS score (0.84%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
- EPSS
- 0.84% probability · 58th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS 0.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1704843Issue Tracking, Vendor Advisory
- https://security.gentoo.org/glsa/202202-03Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-28/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1704843Issue Tracking, Vendor Advisory
- https://security.gentoo.org/glsa/202202-03Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-28/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.