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

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PublisherGitHub

Article IDGHSA-F8FG-PG57-V4J8

Verified snapshot27 Sept 2026, 08:30 UTC

Linked CVEs1

Linked CVE reports

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

Source and provenance

Original title: XSS: `on*` event-handler filter in `AttributesExtension` bypassed with a U+000C form feed · Advisory · thephpleague/commonmark · GitHub. Captured 27 Sept 2026, 08:30 UTC. The stored article is used for enrichment and change detection; BlackTree does not republish the publisher's full text here.

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