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Medium · 6.1 CVE-2026-104477 EUVD-2026-91853GHSA-gc85-xrjc-cv75

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

Published Oct 2, 2026 · Updated Oct 5, 2026 · Assigned by VulnCheck

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.

Affected products

VendorProductAffectedFixed
showdownjs showdown ≤ 2.1.0 —

References