{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2026.5.4"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0723d8d83ff121e732e76b5dffe1b6648c69d596"
            },
            {
              "fixed": "894a68acb678afc382fe5ea9002e61ab7f862011"
            }
          ],
          "repo": "https://github.com/home-assistant/core",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64823.json"
  },
  "details": "Home Assistant Core before 2026.5.4 contains a cross-site scripting vulnerability in the Shelly integration's async_get_media_image() method that allows attackers controlling a Shelly device's thumb field to serve arbitrary HTML content by supplying a data URI with a text/html content type without validation against an image-only allowlist. Attackers can cause the media player proxy endpoint to serve attacker-controlled bytes with Content-Type text/html in the Home Assistant web origin, enabling theft of session tokens from local storage and authenticated calls to sensitive service endpoints including lock, alarm, and cover controls.",
  "id": "CVE-2026-64823",
  "modified": "2026-07-24T03:56:43.744519671Z",
  "published": "2026-07-21T15:16:03.790Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64823.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/home-assistant/core/releases/tag/2026.5.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64823"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/home-assistant-core-xss-via-shelly-media-player-py-thumb-uri"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/home-assistant/core/pull/171585"
    },
    {
      "type": "FIX",
      "url": "https://github.com/home-assistant/core/commit/894a68acb678afc382fe5ea9002e61ab7f862011"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/home-assistant/core"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Home Assistant Core \u003c 2026.5.4 XSS via Shelly media_player.py thumb URI"
}