CVE-2023-6209 Path traversal in Firefox
Attackers can override the specified host using path traversal in relative URLs, potentially bypassing security controls in Firefox and Thunderbird.
- 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-2023-6209?
CVE-2023-6209 is a medium-severity path traversal vulnerability in Debian Debian Linux, published on 21 Nov 2023. 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
Relative URLs starting with three slashes were incorrectly parsed, and a path-traversal "/../" part in the path could be used to override the specified host. This could contribute to security problems in web sites. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.
Weakness: CWE-22
Which versions are affected by CVE-2023-6209?
It affects 4 products.
Products include Debian Debian Linux, Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.
How do I fix CVE-2023-6209?
Upgrade to a fixed version.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2023-6209 being exploited?
There is no known exploitation of CVE-2023-6209 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2023-6209, GHSA-c2fx-6qc9-26x9, OESA-2025-2591, UBUNTU-CVE-2023-6209.