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CVE PROGRAM SOURCE RECORD8.7 High

CVE-2026-86430

league/commonmark before 2.9.1 Denial of Service via parsing

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Status
Published
Published
Updated
Assigning organization
VulnCheck

Description

league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detection, reference link label lookup, and emphasis delimiter processing that perform super-linear work on crafted input. Attackers can submit specially crafted Markdown with long backtick runs, nested brackets, or delimiter sequences to consume disproportionate CPU time and prevent legitimate requests from completing.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

thephpleague commonmark

Default version status: unaffected

  • 0.6.0 to < 2.9.1affected
  • 2.9.1unaffected
pkg:composer/league/commonmark

References