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 through the AttributesListener::processDocument and...

CVE-2026-86431

league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte e.g. \x0Conclick="alert1" bypasses the AttributesHelper::filterAttributes 'on' event-handle...

CVE-2026-86428

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming...

CVE-2026-86429

The league/commonmark thephpleague/commonmark library in versions = 1.5.0 and 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment they are not enabled by default and are excluded from the...

DEBIAN-CVE-2026-86429

The league/commonmark thephpleague/commonmark library in versions = 1.5.0 and 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment they are not enabled by default and are excluded from the...

DEBIAN-CVE-2026-86431

league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte e.g. \x0Conclick="alert1" bypasses the AttributesHelper::filterAttributes 'on' event-handle...

DEBIAN-CVE-2026-86428

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming...

CVE-2026-86431 commonmark before 2.9.1 XSS via AttributesExtension form feed bypass

league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte e.g. \x0Conclick="alert1" bypasses the AttributesHelper::filterAttributes 'on' event-handle...

CVE-2026-86431 commonmark before 2.9.1 XSS via AttributesExtension form feed bypass

league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte e.g. \x0Conclick="alert1" bypasses the AttributesHelper::filterAttributes 'on' event-handle...

EUVD-2026-72389

league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte e.g. \x0Conclick="alert1" bypasses the AttributesHelper::filterAttributes 'on' event-handle...

CVE-2026-86431

league/commonmark (thephpleague/commonmark) versions >= 2.7.0 and

CVE-2026-86431 commonmark before 2.9.1 XSS via AttributesExtension form feed bypass

league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte e.g. \x0Conclick="alert1" bypasses the AttributesHelper::filterAttributes 'on' event-handle...

EUVD-2026-72386

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming...

CVE-2026-86429 commonmark before 2.9.1 Denial of Service via SmartPunct and Attributes

The league/commonmark thephpleague/commonmark library in versions = 1.5.0 and 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment they are not enabled by default and are excluded from the...

CVE-2026-86428 commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming...

CVE-2026-86428

PHP League CommonMark (versions 1.5.0 through before 2.10.0 ) is affected by a denial-of-service vulnerability in the AttributesExtension . When processing Markdown containing numerous distinctly-named attributes, the extension performs quadratic-time attribute merging and filtering , consuming d...

CVE-2026-86428 commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming...

EUVD-2026-72387

The league/commonmark thephpleague/commonmark library in versions = 1.5.0 and 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment they are not enabled by default and are excluded from the...

CVE-2026-86428 commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes

commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming...

CVE-2026-86429: Inefficient Algorithmic Complexity

The league/commonmark thephpleague/commonmark library in versions = 1.5.0 and 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment they are not enabled by default and are excluded from the...