CVE-2026-105829
CVE-2026-105829
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Weakness classification (CWE)
References
- github.com/thephpleague/commonmark/security/advisories/GHSA-97jj-33gv-5xf9 (vendor-advisory)
- www.vulncheck.com/advisories/league-commonmark-1.3.0-before-2.10.2-stored-xss-v… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-105829?
- CVE-2026-105829 is a medium-severity vulnerability, classified under Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). CVSS score: 6.1/10. Published 2026-10-08.
- How severe is CVE-2026-105829?
- Medium severity. CVSS v3 base score is 6.1 out of 10.