Executive brief
The Home Assistant Community Store (HACS), a popular integration for managing custom smart home components, contains a security flaw that allows unauthorized individuals to access sensitive system files. By exploiting this vulnerability, an attacker can steal administrative credentials and gain full control over a user's Home Assistant instance. This could lead to the unauthorized monitoring of a home, manipulation of smart devices, and access to private user data.
Technical details
A path traversal vulnerability (CWE-22) exists in the HACS integration for Home Assistant due to insufficient input validation on the '/hacsfiles/' endpoint. An unauthenticated remote attacker can use directory traversal sequences (e.g., '../../') to escape the intended directory and read arbitrary files from the host system. Specifically, attackers can target the '.storage/auth' file, which contains user credentials and refresh tokens. By extracting these secrets, an attacker can craft valid JSON Web Tokens (JWT) to bypass authentication and achieve full administrative access to the Home Assistant instance. The vulnerability is addressed in HACS version 1.10.0.
Affected products
- Home Assistant Home Assistant Community Store (HACS) < 1.10.0
Timeline
- 2021-01-28: disclosed: Initial exploit published by Lyghtnox
- 2021-01-29: other: Exploit added to Exploit-DB
- 2026-05-16: advisory: NVD and VulnCheck published formal advisory details