GHSA-4qw4-jpp4-8gvp
Unbounded resource exhaustion in cmark-gfm autolink extension may lead to denial of service
- Severity
- Medium
- The publisher's own rating, not a CVSS score
- Exploit chance (EPSS)
- —
- No score published
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
0.23.6- Upgrade commonmarker to this version or later
Description
Impact
CommonMarker uses cmark-gfm for rendering Github Flavored Markdown. A polynomial time complexity issue in cmark-gfm's autolink extension may lead to unbounded resource exhaustion and subsequent denial of service.
Patches
This vulnerability has been patched in the following CommonMarker release:
- v0.23.6
Workarounds
Disable use of the autolink extension.
References
https://github.com/gjtorikian/commonmarker/pull/190 https://github.com/github/cmark-gfm/security/advisories/GHSA-cgh3-p57x-9q7q https://en.wikipedia.org/wiki/Time_complexity
For more information
If you have any questions or comments about this advisory:
- Open an issue in github/cmark-gfm
Acknowledgements
We would like to thank Legit Security for reporting this vulnerability.
Affected versions
RubyGems
| Package | Vulnerable | Fixed in |
|---|---|---|
| commonmarker | < 0.23.6 |
0.23.6 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
commonmarker RubyGems → 0.23.6
- bundler
bundle update commonmarker # Gemfile: gem "commonmarker", ">= 0.23.6"
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. 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.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Packages
Other links
Timeline
- Published
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-7vh7-fw88-wj87 Several quadratic complexity bugs may lead to denial of service in Commonmarker | Medium | Also affects commonmarker |
| GHSA-48wp-p9qv-4j64 Commonmarker vulnerable to to several quadratic complexity bugs that may lead to denial of service | Medium | Also affects commonmarker |
| GHSA-636f-xm5j-pj9m Several quadratic complexity bugs may lead to denial of service in Commonmarker | Medium | Also affects commonmarker |
| GHSA-fmx4-26r3-wxpf Integer overflow in cmark-gfm table parsing extension leads to heap memory corruption | Critical | Also affects commonmarker |
| GHSA-cggf-277g-3q54 pypdf has possible large memory usage when parsing page tree | High | Same weakness, CWE-400 |
| GHSA-3g3m-2fjr-6pw4 Glob: AbortSignal cancellation bypass allows post-timeout filesystem traversal | Medium | Same weakness, CWE-400 |
| GHSA-42gh-23hr-vphw pypdf has possible long runtimes when retrieving page labels | High | Same weakness, CWE-400 |
| GHSA-4vqv-7265-gm2w pypdf has possible large memory usage for exceptions in strict mode | High | Same weakness, CWE-400 |
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