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Advisory record · GHSA-97jj-33gv-5xf9

league/commonmark: DisallowedRawHtml bypassed when a disallowed tag name ends the raw-HTML literal

CVSS 5.3 MediumEPSS 0.0025 · 16th percentile

Published by the GitHub Advisory Database at 30 Sept 2026, 15:36 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
league/commonmarkPackagist>=1.3.0, <2.10.22.10.2
Identifiers
GHSA-97jj-33gv-5xf9 · CVE-2026-105829 · PKSA-m2dq-1fhr-29b1
Weakness (CWE)
CWE-78 · CWE-79 · CWE-80
Tags
Published
30 Sept 2026
Updated
9 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The league/commonmark package, versions 1.3.0 up to 2.10.2 (fixed in 2.10.2), has a flaw in the DisallowedRawHtml extension: a disallowed tag name at the very end of a raw HTML line, such as a bare script or iframe opening tag, is not escaped. An attacker who can post Markdown can use this to inject script into rendered pages when html_input is set to allow, which is the default with the GFM extension, and no account beyond posting content is described. Upgrade to league/commonmark 2.10.2 or later; setting html_input to escape or strip also mitigates the issue.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
5.3 Medium 4.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N CNA (VulnCheck)
  • CISA KEV Not listed.
  • EPSS 0.0025, the 16th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 21 Sept 2026, 12:30 UTC Published by the maintainers as a GitHub repository advisory
  2. 31 Oct 2026, 13:54 UTC First seen by agentprime
  3. 31 Oct 2026, 13:54 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.