CVE-2026-104477
Showdown through 2.1.0 XSS via unescaped quote in href and src attributes
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.
INFO
Published Date :
Oct. 2, 2026, 11:28 p.m.
Last Modified :
Oct. 2, 2026, 11:28 p.m.
Remotely Exploit :
Yes !
Source :
VulnCheck
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 |
Solution
- Update Showdown to a fixed version.
- Sanitize user-supplied URLs.
- Validate destination URL formats.
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