CVE-2021-38186

MEDIUM6.1EPSS 0.20%

XSS in `comrak`

Published: 8/25/2021Modified: 11/8/2023

Description

[comrak](https://github.com/kivikakk/comrak) operates by default in a "safe" mode of operation where unsafe content, such as arbitrary raw HTML or URLs with non-standard schemes, are not permitted in the output. This is per the reference GFM implementation, [cmark-gfm](https://github.com/github/cmark). Ampersands were not being correctly escaped in link targets, making it possible to fashion unsafe URLs using schemes like `data:` or `javascript:` by entering them as HTML entities, e.g. `&#x64&#x61&#x74&#x61&#x3a`. The intended behaviour, demonstrated upstream, is that these should be escaped and therefore harmless, but this behaviour was broken in comrak.

Affected packages (2)

CVSS scores

SourceVersionSeverityVector
osvCVSS 3.1MEDIUM6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References (7)