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.

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.

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.

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.

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.