Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag

{
  "id": "4fb69cbda1a94f12ffb3711b401897414f5f0fd79a7a2b9700b0ed0213e21061",
  "url": "https://osv.dev/vulnerability/CVE-2026-49210",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag",
    "summary": "Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, Symfony\\UX\\LiveComponent\\Util\\ChildComponentPartialRenderer::createHtml() interpolates the client-controlled children[id].tag value from LiveComponentSubscriber and InterceptChildComponentRenderSubscriber directly into HTML as a tag name without escaping or validation, allowing arbitrary HTML, including",
    "evidence": "osv:CVE-2026-49210",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2026-49210",
      "aliases": [
        "CVE-2026-49210",
        "GHSA-38x5-rcv4-xf7x"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/symfony/ux",
              "type": "GIT",
              "events": [
                {
                  "introduced": "8e214d4461a62f78956607500d9417ddc2f451ef"
                },
                {
                  "fixed": "5ccec9746faa28d79a87138042174c3853d5702b"
                },
                {
                  "introduced": "3cef8e0d9557bbde60c3f1bfd2cbb1004af7fc9a"
                },
                {
                  "fixed": "fbc5e9a1bda7e4556be21bb1d970f382760ed9a9"
                },
                {
                  "fixed": "4c883fdb0f0e7ea577f851bd457024f7e88788c9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:symfony:ux:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.8.0"
                      },
                      {
                        "fixed": "2.36.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:symfony:ux:3.0.0:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.0.0"
                      },
                      {
                        "last_affected": "3.0.0"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "fbc5e9a1bda7e4556be21bb1d970f382760ed9a9"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5ccec9746faa28d79a87138042174c3853d5702b"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.36.0"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4c883fdb0f0e7ea577f851bd457024f7e88788c9"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v3.1.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "3.0.0",
            "v2.35.0",
            "v3.0.0",
            "v2.34.0",
            "v2.33.0",
            "v2.32.0",
            "v2.31.0",
            "v2.30.0",
            "v2.29.2",
            "v2.29.1",
            "v2.29.0",
            "v2.28.2",
            "v2.28.1",
            "v2.28.0",
            "v2.27.0",
            "v2.26.0",
            "v2.26.1",
            "v2.25.2",
            "v2.25.1",
            "v2.25.0",
            "v2.24.0",
            "v2.23.0",
            "v2.22.1",
            "v2.22.0",
            "v2.21.0",
            "v2.9.1",
            "v2.20.0",
            "v2.19.3",
            "v2.19.2",
            "v2.19.0",
            "v2.19.1",
            "v2.18.1",
            "v2.18.0",
            "v2.17.0",
            "v2.16.0",
            "v2.14.0",
            "v2.15.0",
            "v2.14.2",
            "v2.14.1",
            "v2.13.1",
            "v2.13.3",
            "v2.13.2",
            "v2.13.0",
            "v2.12.0",
            "v2.11.1",
            "v2.11.2",
            "v2.11.0",
            "v2.10.0",
            "v2.8.1",
            "v2.9.0",
            "v2.8.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49210.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.540489036Z",
      "provider": "osv",
      "references": [
        "https://github.com/symfony/ux/releases/tag/v2.36.0",
        "https://github.com/symfony/ux/releases/tag/v3.1.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49210.json",
        "https://github.com/symfony/ux/security/advisories/GHSA-38x5-rcv4-xf7x",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-49210",
        "https://github.com/symfony/ux/commit/fbc5e9a1bda7e4556be21bb1d970f382760ed9a9"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49210.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-49210",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496426,
  "published_at": "2026-07-17T16:09:17.85+00:00"
}