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

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-2026-71478 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-2026-57530

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...

CVE-2026-33347

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...

UBUNTU-CVE-2026-33347

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...

CVE-2026-33347 league/commonmark has an embed extension allowed_domains bypass

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...

CVE-2026-33347

Summary: CVE-2026-33347 affects league/commonmark’s Embed extension DomainFilteringAdapter. A missing hostname boundary assertion in the domain-matching regex allows an attacker-controlled domain (e.g., youtube.com.evil) to bypass the allowlist, potentially treating untrusted content as allowed. ...

CVE-2026-33347

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...

CVE-2026-33347 league/commonmark has an embed extension allowed_domains bypass

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...

CVE-2026-33347

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...

CVE-2026-33347 league/commonmark has an embed extension allowed_domains bypass

league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like...