CVE-2021-29974 Security feature bypass in Firefox
Attackers can bypass HSTS protections on error pages when network partitioning is enabled, allowing potential downgrade attacks despite HTTPS enforcement.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-29974?
CVE-2021-29974 is a medium-severity vulnerability in Mozilla Firefox, published on 5 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2021-29974?
It affects 1 product.
Products include Mozilla Firefox.
How do I fix CVE-2021-29974?
Upgrade to a fixed version.
Is CVE-2021-29974 being exploited?
There is no known exploitation of CVE-2021-29974 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as GHSA-wvgv-pqxg-x8rr, UBUNTU-CVE-2021-29974.