What is CVE-2026-59711?

CVE-2026-59711 is a medium-severity vulnerability in Showdown, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-07-06.

How severe is CVE-2026-59711?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Showdown

CVE-2026-59711

showdown contains a cross-site scripting vulnerability in metadata title handling that allows attackers to inject arbitrary HTML and JavaScript. When completeHTMLDocument option is enabled, unescaped less-than and greater-than characters i…

Vulnerability class: XSS (Cross-Site Scripting)

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.

Affected products

Showdown — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

disclosure@vulncheck.com (product)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-59711?: CVE-2026-59711 is a medium-severity vulnerability in Showdown, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-07-06.
How severe is CVE-2026-59711?: Medium severity. CVSS v3 base score is 6.1 out of 10.