CVE-2026-71497

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.

When a custom `Safelist` permits certain raw-text elements, jsoup may incorrectly sanitize malformed HTML containing a tag name that ends in a control character. The tag may acquire the parsing behavior of a different element, causing content that should remain text to be emitted as active markup after serialization and potentially allowing XSS. jsoup’s built-in Safelists are unaffected. ## Patches Upgrade to jsoup 1.23.1. ## Workarounds Until upgrading, do not permit raw-text elements in custom Safelists used to clean untrusted HTML. ## Additional security considerations This fix addresses malformed tag-name handling only. Permitting raw-text elements in a custom `Safelist` does not make their contents inherently safe. For example, applications that permit `style` must apply appropriate CSS safeguards separately, because jsoup does not parse or sanitize CSS.