| Package | Affected versions | Patched versions |
|---|---|---|
| league/commonmark | < 2.6.0 | 2.6.0 |
Several polynomial time complexity issues in league/commonmark may lead to unbounded resource exhaustion and subsequent denial of service.
Malicious users could trigger that inefficient code with carefully crafted Markdown inputs that are specifically designed to ensure the worst-case performance is reached. Sending multiple such requests in parallel could tie up all available CPU resources and/or PHP-FPM processes, leading to denial of service for legitimate users.
These vulnerabilities have been patched in version 2.6.0. All users on older versions are highly encouraged to upgrade as soon as possible.
If you cannot upgrade, you may be able to mitigate the issues by:
memory_limit and max_execution_time PHP configurations to prevent runaway resource usageMost of these issues were discovered in other Markdown parsers. You can read more about them here:
Running one of these products? Scan your site to see whether it exposes a vulnerable version.
Scan my site freeFor general information about this type of issue: