What happened
jsoup is a Java library for working with real-world HTML. From 1.14.3 until 1.23.1, jsoup's HTML parser could incorrectly handle a malformed tag name ending in a control character, causing the tag to acquire the parsing behavior of a different element. When a custom Safelist permits certain raw-text elements, this misparsing can cause content that should remain inert text to be emitted as active markup after serialization, potentially resulting in cross-site scripting. jsoup's built-in Safelists are not affected. This issue is fixed in version 1.23.1.
Affected versions
jsoup: >= 1.14.3, < 1.23.1 Fixed: See vendor advisory.
Why it matters
Review the vendor advisory and exposure of the affected product to determine operational impact.
Detection & mitigation
- Apply vendor-provided updates or mitigations.
- Review affected product exposure and access logs.
Public PoC references
No public PoC reference has passed the current publication threshold.