CVE-2026-104477 (GCVE-0-2026-104477)

Vulnerability from cvelistv5 – Published: 2026-10-02 23:28 – Updated: 2026-10-02 23:28
VLAI
Title
Showdown through 2.1.0 XSS via unescaped quote in href and src attributes
Summary
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.
Severity
5.3 (Medium)
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
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
Impacted products
Vendor Product Version
showdownjs showdown Affected: 0 , ≤ 2.1.0 (semver)
    cpe:2.3:a:showdownjs:showdown:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-06-27 00:00
Credits
Muhammad Sobirov
Show details on NVD website
To clipboard 

{
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        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/showdown",
          "product": "showdown",
          "vendor": "showdownjs",
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
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      ],
      "cpeApplicability": [
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          "nodes": [
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                  "criteria": "cpe:2.3:a:showdownjs:showdown:*:*:*:*:*:*:*:*",
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                }
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      "descriptions": [
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          "value": "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."
        }
      ],
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            "version": "3.1"
          },
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      ],
      "problemTypes": [
        {
          "descriptions": [
            {
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            }
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      "providerMetadata": {
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        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
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        },
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          "tags": [
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          ],
          "url": "https://github.com/showdownjs/showdown"
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        {
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          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/showdown-through-2.1.0-xss-via-unescaped-quote-in-href-and-src-attributes"
        }
      ],
      "title": "Showdown through 2.1.0 XSS via unescaped quote in href and src attributes",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-104477",
    "datePublished": "2026-10-02T23:28:47.414Z",
    "dateReserved": "2026-10-02T00:55:58.388Z",
    "dateUpdated": "2026-10-02T23:28:47.414Z",
    "state": "PUBLISHED"
  },
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      "percentile": "0.07542"
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    "redhat_vex": {
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      "current_release_date": "2026-10-03T00:54:04+00:00",
      "cve": "CVE-2026-104477",
      "id": "CVE-2026-104477",
      "initial_release_date": "2026-10-02T23:28:47.414000+00:00",
      "product_status:known_affected": "29",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "showdown: showdown: Cross-site scripting via unescaped double quotes in link and image attributes",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-104477.json",
      "version": "3"
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


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