CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

Cross-site Scripting (XSS)

Overview league/commonmark is a PHP-based Markdown parser which supports the full CommonMark spec. It is based on the CommonMark JS reference implementation. Affected versions of this package are vulnerable to Cross-site Scripting XSS via the DisallowedRawHtml extension when a newline, tab, or...

DEBIAN-CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

UBUNTU-CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838 league/commonmark: DisallowedRawHtml extension bypass via whitespace in HTML tag names

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838 league/commonmark: DisallowedRawHtml extension bypass via whitespace in HTML tag names

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CVE-2026-30838

CVE-2026-30838 affects league/commonmark, a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting ASCII whitespace between a disallowed HTML tag name and the closing >, e.g., , enabling a cross-site scripting (XSS) vector for applications tha...

CVE-2026-30838 league/commonmark: DisallowedRawHtml extension bypass via whitespace in HTML tag names

league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a...

CommonMark has DisallowedRawHtml extension bypass via whitespace in HTML tag names

Impact The DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing . For example, would pass through unfiltered and be rendered as a valid HTML tag by browsers. This is a cross-site scripting X...

PT-2026-23795

Name of the Vulnerable Software and Affected Versions league/commonmark versions prior to 2.8.1 Description The DisallowedRawHtml extension in league/commonmark can be bypassed by inserting ASCII whitespace characters between a disallowed HTML tag name and the closing ''. For example, would pass...