CVE-2022-39209 Uncontrolled Resource Consumption in cmark-gfm
Attackers can cause denial of service in cmark-gfm via resource exhaustion when the autolink extension is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-39209?
CVE-2022-39209 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 15 Sep 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. In versions prior to 0.29.0.gfm.6 a polynomial time complexity issue in cmark-gfm's autolink extension may lead to unbounded resource exhaustion and subsequent denial of service. Users may verify the patch by running `python3 -c 'print("![l"* 100000 + "\n")' | ./cmark-gfm -e autolink`, which will resource exhaust on unpatched cmark-gfm but render correctly on patched cmark-gfm. This vulnerability has been patched in 0.29.0.gfm.6. Users are advised to upgrade. Users unable to upgrade should disable the use of the autolink extension.
Which versions are affected by CVE-2022-39209?
It affects 2 products.
Products include Fedoraproject Fedora, Github Cmark-Gfm.
How do I fix CVE-2022-39209?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2022-39209 being exploited?
There is no known exploitation of CVE-2022-39209 in the wild and no public exploit code.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as DEBIAN-CVE-2022-39209, GHSA-cgh3-p57x-9q7q, UBUNTU-CVE-2022-39209.