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Medium

Invoking incorrect handling of HTML elements in foreign content in golang.org/x/net/html

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-42502
Confirmed fixed CVEs
Not specified
Updated in this feed
2 Nov 2026, 17:32 UTC · Revision 1

Source evidence

Invoking incorrect handling of HTML elements in foreign content in golang.org/x/net/html

core-osv · Original source

Published 22 May 2026, 15:01 UTC

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.

osv:CVE-2026-42502
Complete source record
{
  "id": "dc46febc9e58810b5cb208192e011b83f669e176fade463074595e7b211bb1d9",
  "url": "https://osv.dev/vulnerability/CVE-2026-42502",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Invoking incorrect handling of HTML elements in foreign content 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-2026-42502",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-42502",
      "aliases": [
        "CVE-2026-42502",
        "GO-2026-5027"
      ],
      "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-2026-42502.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.376850430Z",
      "provider": "osv",
      "references": [
        "https://go.dev/cl/781701",
        "https://go.dev/issue/79572",
        "https://groups.google.com/g/golang-announce/c/iI-mYSI0lu8",
        "https://pkg.go.dev",
        "https://pkg.go.dev/vuln/GO-2026-5027",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42502.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42502"
      ],
      "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/2026/42xxx/CVE-2026-42502.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-42502",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 487748,
  "published_at": "2026-05-22T15:01:21.649+00:00"
}