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 via the FootnoteExtension process. An attacker can...

league/commonmark: Quadratic-time denial of service when parsing crafted Markdown

Impact Affected versions of league/commonmark can have quadratic time complexity when parsing specially crafted Markdown lines. In practical terms, doubling the length of an affected line can make the parser perform roughly four times as much work. The parser identifies locations using character...

Excessive Platform Resource Consumption within a Loop

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 Excessive Platform Resource Consumption within a Loop through the Markdown parsing...

GHSA-2Q4P-G7HV-5RGV league/commonmark: Quadratic-time denial of service when parsing crafted Markdown

Impact Affected versions of league/commonmark can have quadratic time complexity when parsing specially crafted Markdown lines. In practical terms, doubling the length of an affected line can make the parser perform roughly four times as much work. The parser identifies locations using character...

CVE-2026-71488 league/commonmark: Quadratic-time denial of service when parsing crafted Markdown

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translat...

CVE-2026-71488

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translat...

CVE-2026-71488

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translat...

CVE-2026-71488 league/commonmark: Quadratic-time denial of service when parsing crafted Markdown

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translat...

CVE-2026-71488

The CVE concerns league/commonmark (PHP) with a vulnerability in versions 0.6.0–2.9.0 where crafted Markdown can trigger quadratic-time processing during parsing/conversion. The root cause involves repeatedly rescanning growing segments to translate character positions to byte positions, and the ...

Incomplete Denylist to Cross-Site Scripting

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 Incomplete Denylist to Cross-Site Scripting via the filterAttributes process. An attack...

CVE-2026-71478

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a...

CVE-2026-71478 league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a...

CVE-2026-71478

Summary. league/commonmark 1.5.0–2.8.3 is vulnerable due to the AttributesExtension href/src unsafe-link filter bypass when control bytes are embedded in a javascript: URL. The browser may execute the script after the URL is parsed, even with allow_unsafe_links enabled. The issue is caused by ins...

CVE-2026-71478 league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a...

CVE-2026-71478

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a...

CVE-2026-57530

Milkdown before 7.21.3 contains a stored cross-site scripting vulnerability in the @milkdown/preset-commonmark and @milkdown/components packages that allows attackers with document write access to execute arbitrary JavaScript in the browser context of any user who opens the document or clicks a...

PT-2026-64409

Name of the Vulnerable Software and Affected Versions Milkdown versions prior to 7.21.3 Description A stored cross-site scripting issue exists in the @milkdown/preset-commonmark and @milkdown/components packages. Attackers with document write access can execute arbitrary JavaScript in the browser...

Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS : league/commonmark vulnerabilities (USN-8194-1)

The remote Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8194-1 advisory. It was discovered that league/commonmark did not properly restrict unsafe attributes when the Attributes extension was enabled. A...

USN-8194-1 php-league-commonmark vulnerabilities

It was discovered that league/commonmark did not properly restrict unsafe attributes when the Attributes extension was enabled. An attacker could possibly use this issue to cause cross-site scripting by injecting malicious code into rendered HTML. This issue only affected Ubuntu 22.04 LTS and...

USN-8194-1: league/commonmark vulnerabilities

It was discovered that league/commonmark did not properly restrict unsafe attributes when the Attributes extension was enabled. An attacker could possibly use this issue to cause cross-site scripting by injecting malicious code into rendered HTML. This issue only affected Ubuntu 22.04 LTS and...