๐Ÿ” CVE Alert

CVE-2026-64823

MEDIUM 4.7

Home Assistant Core < 2026.5.4 XSS via Shelly media_player.py thumb URI

CVSS Score
4.7
EPSS Score
0.2%
EPSS Percentile
8th

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.

CWE CWE-79
Vendor home-assistant
Product home assistant core
Published Jul 21, 2026
Last Updated Jul 22, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

Affected Versions

home-assistant / Home Assistant Core
0 < 2026.5.4

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
github.com: https://github.com/home-assistant/core/releases/tag/2026.5.4 github.com: https://github.com/home-assistant/core/pull/171585 github.com: https://github.com/home-assistant/core/commit/894a68acb678afc382fe5ea9002e61ab7f862011 vulncheck.com: https://www.vulncheck.com/advisories/home-assistant-core-xss-via-shelly-media-player-py-thumb-uri

Credits

Harish Kolla (@Har1sh-k)