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...

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...

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...

Linux Distros Unpatched Vulnerability : CVE-2026-86431

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - league/commonmark thephpleague/commonmark versions = 2.7.0 and 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an...

PT-2026-86797

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-handler...

GHSA-F8FG-PG57-V4J8 league/commonmark XSS: `on*` event-handler filter in `AttributesExtension` bypassed with a U+000C form feed

Summary The AttributesExtension documents a security guarantee: Note: Attributes starting with on e.g. onclick or onerror are capable of executing JavaScript code and are therefore never allowed by default. You must explicitly add them to the allow list if you want to use them. —...