CVE-2019-11747 Security feature bypass in Firefox
Attackers can bypass HSTS protection for pre-loaded sites if users manually enter HTTP URLs after using the Forget feature, exposing traffic to interception.
- 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-2019-11747?
CVE-2019-11747 is a medium-severity vulnerability in Mozilla Firefox, published on 27 Sep 2019. 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
The "Forget about this site" feature in the History pane is intended to remove all saved user data that indicates a user has visited a site. This includes removing any HTTP Strict Transport Security (HSTS) settings received from sites that use it. Due to a bug, sites on the pre-load list also have their HSTS setting removed. On the next visit to that site if the user specifies an http: URL rather than secure https: they will not be protected by the pre-loaded HSTS setting. After that visit the site's HSTS setting will be restored. This vulnerability affects Firefox < 69 and Firefox ESR < 68.1.
Weakness: CWE-665
Which versions are affected by CVE-2019-11747?
It affects 2 products.
Products include Mozilla Firefox, Mozilla Firefox Esr.
How do I fix CVE-2019-11747?
Upgrade to a fixed version.
Is CVE-2019-11747 being exploited?
There is no known exploitation of CVE-2019-11747 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2019-11747, GHSA-9f7j-g98g-532j, UBUNTU-CVE-2019-11747.