League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass
Published Oct 8, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
League CommonMark from 1.3.0 before 2.10.2 contains a cross-site scripting vulnerability that allows users posting Markdown to bypass the DisallowedRawHtml extension by ending raw HTML with a bare disallowed tag name. Attackers can place a lone <script or <iframe line followed by a block supplying attributes like src or onload, executing stored scripts in viewers' browsers under default GFM settings.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- LOW
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Security advisory ↗
- VulnCheck Advisory: League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass ↗
Record history
Published Oct 8, 2026 · Last refreshed Nov 3, 2026