PyMdown Extensions is a set of extensions for the Python-Markdown markdown project. Versions prior to 10.16.1 have a ReDOS bug found within the figure caption extension (pymdownx.blocks.caption). In systems that take unchecked user content, this could cause long hanges when processing the data if a malicious payload was crafted. This issue is patched in Release 10.16.1. As a workaround, those who process unknown user content without timeouts or other safeguards in place to prevent really large, malicious content being aimed at systems may avoid the use of pymdownx.blocks.caption until theyre able to upgrade.
Weakness
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Pymdown_extensions | Facelessuser | * | 10.16.1 (excluding) |
| Pymdown-extensions | Ubuntu | plucky | * |
| Pymdown-extensions | Ubuntu | questing | * |