CVE-2026-105829 League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone script or iframe line followed by a block supplying...

CVE-2026-105829

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone script or iframe line followed by a block supplying...

EUVD-2026-95016

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone script or iframe line followed by a block supplying...

CVE-2026-105829 League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone script or iframe line followed by a block supplying...

CVE-2026-105829

The League CommonMark library (versions 1.3.0 before 2.10.2 ) is vulnerable to a Stored Cross-Site Scripting (XSS) flaw. The root cause is a bypass in the DisallowedRawHtml extension, where an attacker can evade restrictions by ending a raw HTML tag with a bare disallowed tag name. By placing a l...

CLSA-2026-1791458521 TuxCare security update for league/commonmark (1 CVE)

TuxCare rebuilt league/commonmark to address 1 CVE. Fixed in 1.6.7-p6+tuxcare...

CLSA-2026-1791458446 TuxCare security update for league/commonmark (2 CVEs)

TuxCare rebuilt league/commonmark to address 2 CVEs. Fixed in 2.8.2-p4+tuxcare...

CLSA-2026-1791458367 TuxCare security update for league/commonmark (2 CVEs)

TuxCare rebuilt league/commonmark to address 2 CVEs. Fixed in 2.7.1-p4+tuxcare...

PT-2026-107989

league/commonmark from 2.0.0 before 2.10.2 contains a quadratic-time denial of service vulnerability in the GitHub Flavored Markdown Table extension's TableStartParser::tryStart block-start scan. Unauthenticated attackers can submit a large paragraph of pipe-free lines not starting with letters,...

CVE-2026-105830: Uncontrolled Resource Consumption

league/commonmark from 2.0.0 before 2.10.2 contains a quadratic-time denial of service vulnerability in the GitHub Flavored Markdown Table extension's TableStartParser::tryStart block-start scan. Unauthenticated attackers can submit a large paragraph of pipe-free lines not starting with letters,...

PT-2026-117104

TuxCare rebuilt league/commonmark to address 1 CVE. Fixed in 1.6.7-p6+tuxcare...

PT-2026-117103

TuxCare rebuilt league/commonmark to address 2 CVEs. Fixed in 2.8.2-p4+tuxcare...

PT-2026-117102

TuxCare rebuilt league/commonmark to address 2 CVEs. Fixed in 2.7.1-p4+tuxcare...

CVE-2026-105829: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone...

GHSA-97JJ-33GV-5XF9 league/commonmark: DisallowedRawHtml bypassed when a disallowed tag name ends the raw-HTML literal

Summary The DisallowedRawHtml extension does not escape a disallowed tag when the tag name is the last thing in the raw HTML. A Markdown line containing just /i The trailing character class requires one character after the tag name. The block parser does not: RegexHelper::PARTIALHTMLBLOCKOPEN...

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 in the DisallowedRawHtml process when a disallowed tag name...

league/commonmark: DisallowedRawHtml bypassed when a disallowed tag name ends the raw-HTML literal

Summary The DisallowedRawHtml extension does not escape a disallowed tag when the tag name is the last thing in the raw HTML. A Markdown line containing just /i The trailing character class requires one character after the tag name. The block parser does not: RegexHelper::PARTIALHTMLBLOCKOPEN...

league/commonmark: Quadratic-time denial of service in the GitHub Flavored Markdown Table extension block-start scan

Summary league/commonmark's GitHub Flavored Markdown Table extension registers TableStartParser as a block-start parser. While a paragraph is the active block, the core block parser calls TableStartParser::tryStart on every non-blank line. Its first action fetches the entire growing paragraph...

GHSA-3Q6V-R5MR-HXV8 league/commonmark: Quadratic-time denial of service in the GitHub Flavored Markdown Table extension block-start scan

Summary league/commonmark's GitHub Flavored Markdown Table extension registers TableStartParser as a block-start parser. While a paragraph is the active block, the core block parser calls TableStartParser::tryStart on every non-blank line. Its first action fetches the entire growing paragraph...

Inefficient Algorithmic Complexity

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 Inefficient Algorithmic Complexity in the TableStartParser::tryStart function. An...