CVE-2026-64823

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

Published Jul 21, 2026 CVSS 4.0 · 2.1 Low EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Home-assistant
Home-assistant home-assistant
CPEs cpe:2.3:a:home-assistant:home-assistant:*:*:*:*:*:*:*:*
Vendors & Products Home-assistant
Home-assistant home-assistant
Type Values Removed Values Added
Description 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.
Title Home Assistant Core < 2026.5.4 XSS via Shelly media_player.py thumb URI
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 2.1, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 8, 2026, 2:07 PM
Reserved
Jul 20, 2026, 6:27 PM
Status
Deferred
Published
Jul 21, 2026, 4:17 PM
Modified
Oct 24, 2026, 7:10 PM