Invoking duplicate attributes can cause XSS in golang.org/x/net/html

{
  "id": "4156e813b67ab1e85ef488143672661bc91b8d446284d36e3dab7aab97eebe51",
  "url": "https://osv.dev/vulnerability/CVE-2026-27136",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Invoking duplicate attributes can cause XSS in golang.org/x/net/html",
    "summary": "Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.",
    "evidence": "osv:CVE-2026-27136",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-27136",
      "aliases": [
        "CVE-2026-27136",
        "GO-2026-5030"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/golang/net",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "7770ec48d03fec35e378665337b4faca93c38423"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:golang:net:*:*:*:*:*:go:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.55.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.54.0",
            "v0.41.0",
            "v0.53.0",
            "v0.52.0",
            "v0.51.0",
            "v0.50.0",
            "v0.49.0",
            "v0.48.0",
            "v0.47.0",
            "v0.46.0",
            "v0.45.0",
            "v0.44.0",
            "v0.43.0",
            "v0.42.0",
            "v0.40.0",
            "v0.39.0",
            "v0.38.0",
            "v0.37.0",
            "v0.36.0",
            "v0.35.0",
            "v0.34.0",
            "v0.33.0",
            "v0.32.0",
            "v0.31.0",
            "v0.30.0",
            "v0.29.0",
            "v0.28.0",
            "v0.27.0",
            "v0.26.0",
            "v0.25.0",
            "v0.24.0",
            "v0.23.0",
            "v0.19.0",
            "v0.22.0",
            "v0.21.0",
            "v0.20.0",
            "v0.18.0",
            "v0.17.0",
            "v0.16.0",
            "v0.15.0",
            "v0.14.0",
            "v0.13.0",
            "v0.12.0",
            "v0.11.0",
            "v0.10.0",
            "v0.9.0",
            "v0.8.0",
            "v0.7.0",
            "v0.4.0",
            "v0.6.0",
            "v0.5.0",
            "v0.3.0",
            "v0.2.0",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27136.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.953532155Z",
      "provider": "osv",
      "references": [
        "https://go.dev/cl/781685",
        "https://go.dev/issue/79575",
        "https://groups.google.com/g/golang-announce/c/iI-mYSI0lu8",
        "https://pkg.go.dev",
        "https://pkg.go.dev/vuln/GO-2026-5030",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27136.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-27136"
      ],
      "provider_metadata": {
        "cna_assigner": "Go",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "0.55.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27136.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27136",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496870,
  "published_at": "2026-05-22T15:01:22.111+00:00"
}