PHP League CommonMark vulnerable to Cross-Site Scripting (XSS)
Date: 2022-05
Affected: composer/league/commonmark
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2018-20583
CWE: CWE-79
CVSS: 6.1 (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)

Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library versions 0.15.6 through 0.18.x before 0.18.1 allows remote attackers to insert unsafe URLs into HTML (even if allow_unsafe_links is false) via a newline character (e.g., writing javascript as javascri%0apt).


Mitigations:

Architectural layers (MAESTRO):