Impact

Special patterns with length > 50K chars can slow down parser significantly.

js const md = require('markdown-it')();

md.render(x ${' '.repeat(150000)} x \nx);

Patches

Upgrade to v12.3.2+

Workarounds

No.

References

Fix + test sample: https://github.com/markdown-it/markdown-it/commit/ffc49ab46b5b751cd2be0aabb146f2ef84986101

A vulnerability was found in markdown-it up to 2.x. It has been classified as problematic. Affected is an unknown function of the file lib/common/htmlre.js. The manipulation leads to inefficient regular expression complexity. Upgrading to version 3.0.0 is able to address this issue. The name of the patch is 89c8620157d6e38f9872811620d25138fc9d1b0d. It is recommended to upgrade the affected component. The identifier of this vulnerability is VDB-216852.

markdown-it before 4.1.0 does not block data: URLs.