Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR)

{
  "id": "f50ba3c37417c4c626ed560cf65e0454140b659cb722f2c25a9b25a1d57a1408",
  "url": "https://osv.dev/vulnerability/CVE-2025-15265",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR)",
    "summary": "An SSR XSS exists in async hydration when attacker‑controlled keys are passed to hydratable. The key is embedded inside a to terminate the script and inject arbitrary JavaScript. This enables remote script execution in users' browsers, with potential for session theft and account compromise. This issue affects Svelte: from 5.46.0 before 5.46.3.",
    "evidence": "osv:CVE-2025-15265",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-15265",
      "aliases": [
        "CVE-2025-15265",
        "GHSA-6738-r8g5-qwp3"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/sveltejs/svelte",
              "type": "GIT",
              "events": [
                {
                  "introduced": "435da13fddaf1872a3fb46a7e8a20bb73322148e"
                },
                {
                  "fixed": "ed8dcd063625062f03291f2f086fee75e1dc5105"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "5.46.0"
                      },
                      {
                        "fixed": "5.46.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:svelte:svelte:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "5.46.0"
                      },
                      {
                        "fixed": "5.46.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "svelte@5.46.1",
            "svelte@5.46.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-15265.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.446205063Z",
      "provider": "osv",
      "references": [
        "https://registry.npmjs.org",
        "https://fluidattacks.com/advisories/lydian",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/15xxx/CVE-2025-15265.json",
        "https://github.com/sveltejs/svelte/security/advisories/GHSA-6738-r8g5-qwp3",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-15265"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "Fluid Attacks",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/15xxx/CVE-2025-15265.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-15265",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497090,
  "published_at": "2026-01-15T19:59:41.683+00:00"
}