NIXPKGS-2026-1737

GitHub issue published on

Permalink CVE-2026-44897

6.1 MEDIUM

CVSS version (CVSS): 3.1
Attack Vector (AV): Network (N)
Attack Complexity (AC): Low (L)
Privileges Required (PR): None (N)
User Interaction (UI): Required (R)
Scope (S): Changed (C)
Confidentiality (C): Low (L)
Integrity (I): Low (L)
Availability (A): None (N)
Modified Attack Vector (MAV): Network (N)
Modified Attack Complexity (MAC): Low (L)
Modified Privileges Required (MPR): None (N)
Modified User Interaction (MUI): Required (R)
Modified Confidentiality (MC): Low (L)
Modified Scope (MS): Changed (C)
Modified Integrity (MI): Low (L)
Modified Availability (MA): None (N)

updated an hour ago by @LeSuisse Activity log

Created suggestion 8 hours ago
@LeSuisse accepted an hour ago
@LeSuisse published on GitHub an hour ago

Mistune Heading ID Attribute Injection XSS

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.