LinkWarden: Stored XSS via Client-Side Archive Upload (Unsanitized HTML served from same origin)

{
  "id": "882f3de4d50124f01de713c7a0ea3a64cacb497aee7f5306de1487886fd8cc23",
  "url": "https://osv.dev/vulnerability/CVE-2026-42455",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "LinkWarden: Stored XSS via Client-Side Archive Upload (Unsanitized HTML served from same origin)",
    "summary": "Linkwarden is a self-hosted, open-source collaborative bookmark manager to collect, organize and archive webpages. In versions 2.14.0 and prior, the archive upload endpoint (POST /api/v1/archives/[linkId]?format=4) accepts HTML files (text/html) without sanitizing JavaScript content. When the archive is later accessed via GET /api/v1/archives/[linkId]?format=4, the HTML is served with Content-Type: text/html from the Linkwarden origin, without any Content-Security-Policy header. This allows arbitrary JavaScript execution in the context of the authenticated Linkwarden sessio. At time of publication, there are no publicly available patches.",
    "evidence": "osv:CVE-2026-42455",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-42455",
      "aliases": [
        "CVE-2026-42455",
        "GHSA-fjvg-mch3-j3vg"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/linkwarden/linkwarden",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "815d2faa885bba5f715e80424155e3927a626ea6"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.14.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.14.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.14.0",
            "v2.13.5",
            "v2.13.4",
            "v2.13.3",
            "v2.13.2",
            "v2.13.1",
            "v2.13.0",
            "v2.12.2",
            "v2.12.1",
            "v2.12.0",
            "v2.11.8",
            "v2.11.7",
            "v2.11.6",
            "v2.11.5",
            "v2.11.4",
            "v2.11.3",
            "v2.11.2",
            "v2.11.1",
            "v.2.11.0",
            "v2.10.2",
            "v2.10.1",
            "v2.10.0",
            "v2.9.3",
            "v2.9.2",
            "v2.9.1",
            "v2.9.0",
            "v2.8.4",
            "v2.8.3",
            "v2.8.2",
            "v2.8.1",
            "v2.8.0",
            "v2.4.4",
            "v2.4.3",
            "v2.4.2",
            "v2.4.1",
            "v2.4.0",
            "v2.3.0",
            "v2.2.1",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0",
            "v1.2.5",
            "v1.2.4",
            "v1.2.3",
            "v1.2.2",
            "v1.2.1",
            "v1.2.0",
            "v1.1.0",
            "v1.0.1",
            "v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42455.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:35.862336491Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42455.json",
        "https://github.com/linkwarden/linkwarden/security/advisories/GHSA-fjvg-mch3-j3vg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42455"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42455.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-42455",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 503363,
  "published_at": "2026-05-08T23:10:11.218+00:00"
}