CVE-2026-64823
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
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| home-assistant | Home Assistant Core | 0 < 2026.5.4 | affected |
Weaknesses
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
References
- https://github.com/home-assistant/core/releases/tag/2026.5.4
- https://github.com/home-assistant/core/pull/171585
- https://github.com/home-assistant/core/commit/894a68acb678afc382fe5ea9002e61ab7f862011
- https://www.vulncheck.com/advisories/home-assistant-core-xss-via-shelly-media-player-py-thumb-uri
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