What’s Vulnerable › Vulnerabilities

CVE-2026-105829: League CommonMark 1.3.0 before 2.10.2 Stored XSS via DisallowedRawHtml Bypass

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-08 · updated 2026-10-10
• Weakness: CWE-80

Description

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.

References

• https://github.com/thephpleague/commonmark/security/advisories/GHSA-97jj-33gv-5xf9
• https://www.vulncheck.com/advisories/league-commonmark-1.3.0-before-2.10.2-stored-xss-via-disallowedrawhtml-bypass
• https://github.com/thephpleague/commonmark/security/advisories/GHSA-97jj-33gv-5xf9

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