Low
Home Assistant Core < 2026.5.4 XSS via Shelly media_player.py thumb URI
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-64823
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 18:40 UTC · Revision 1
Source evidence
Home Assistant Core < 2026.5.4 XSS via Shelly media_player.py thumb URI
core-osv · Original sourcePublished 21 Jul 2026, 15:16 UTC
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.
osv:CVE-2026-64823
Complete source record
{
"id": "24d29969db629ae1e51e9b34dabaa1afc4572595e6909c5c8ed1c726d4cc0375",
"url": "https://osv.dev/vulnerability/CVE-2026-64823",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Home Assistant Core < 2026.5.4 XSS via Shelly media_player.py thumb URI",
"summary": "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.",
"evidence": "osv:CVE-2026-64823",
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"modified": "2026-10-28T02:30:38.209336522Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64823.json",
"https://github.com/home-assistant/core/releases/tag/2026.5.4",
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"https://www.vulncheck.com/advisories/home-assistant-core-xss-via-shelly-media-player-py-thumb-uri",
"https://github.com/home-assistant/core/pull/171585",
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"https://github.com/home-assistant/core"
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"source_id": "core-osv",
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"published_at": "2026-07-21T15:16:03.79+00:00"
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