CVE-2026-104477

Showdown through 2.1.0 XSS via unescaped quote in href and src attributes

Published Oct 2, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
Showdown through 2.1.0 contains a cross-site scripting vulnerability in the makehtml link and image subparsers, which fail to escape double quotes in destination URLs placed into href and src attributes. Attackers can craft markdown links or images containing a double quote followed by onerror or onmouseover handlers to execute script when victims view rendered HTML.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Showdown through 2.1.0 contains a cross-site scripting vulnerability in the makehtml link and image subparsers, which fail to escape double quotes in destination URLs placed into href and src attributes. Attackers can craft markdown links or images containing a double quote followed by onerror or onmouseover handlers to execute script when victims view rendered HTML.
Title Showdown through 2.1.0 XSS via unescaped quote in href and src attributes
First Time appeared Showdownjs
Showdownjs showdown
Weaknesses CWE-79
CPEs cpe:2.3:a:showdownjs:showdown:*:*:*:*:*:*:*:*
Vendors & Products Showdownjs
Showdownjs showdown
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 5, 2026, 8:30 PM
Reserved
Oct 2, 2026, 12:55 AM
Status
Awaiting Analysis
Published
Oct 3, 2026, 12:16 AM
Modified
Oct 6, 2026, 4:00 PM
Severity
Moderate
Public date
Oct 2, 2026, 11:28 PM