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.
Published: 2026-10-02
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 02 Oct 2026 23:30:00 +0000

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'}

Subscriptions

Showdownjs Showdown
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-02T23:28:47.414Z

Reserved: 2026-10-02T00:55:58.388Z

Link: CVE-2026-104477

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-03T00:16:35.920

Modified: 2026-10-03T00:16:35.920

Link: CVE-2026-104477

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-03T00:30:19Z

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')