cmark-gfm is GitHubs fork of cmark, a CommonMark parsing and rendering library and program in C. A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. This CVE covers quadratic complexity issues when parsing text which leads with either large numbers of > or - characters. This issue has been addressed in version 0.29.0.gfm.10. Users are advised to upgrade. Users unable to upgrade should validate that their input comes from trusted sources.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Cmark-gfm | Github | * | 0.29.0.gfm.10. (excluding) |
| Red Hat Enterprise Linux 8 | RedHat | pandoc-0:2.0.6-7.el8_10 | * |
| Cmark | Ubuntu | bionic | * |
| Cmark | Ubuntu | focal | * |
| Cmark | Ubuntu | kinetic | * |
| Cmark | Ubuntu | lunar | * |
| Cmark | Ubuntu | mantic | * |
| Cmark | Ubuntu | oracular | * |
| Cmark | Ubuntu | trusty | * |
| Cmark | Ubuntu | xenial | * |
| Cmark-gfm | Ubuntu | kinetic | * |
| Cmark-gfm | Ubuntu | lunar | * |
| Cmark-gfm | Ubuntu | mantic | * |
| Cmark-gfm | Ubuntu | trusty | * |
| Cmark-gfm | Ubuntu | upstream | * |
| Cmark-gfm | Ubuntu | xenial | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.