Executive brief
AdGuard Home, a network-wide software for blocking ads and tracking, is vulnerable to an authentication bypass when running in a specific configuration. An unauthenticated attacker can exploit this flaw to gain full administrative control over the software. This could allow an attacker to change network filtering settings, intercept traffic data, or disable security protections.
Technical details
A path traversal vulnerability (CWE-22) exists in the authglinet middleware of AdGuard Home when the --glinet flag is enabled. The vulnerability stems from unsanitized string concatenation during the construction of the token file path. An unauthenticated remote attacker can provide a specially crafted path traversal sequence (e.g., ../) within the Admin-Token cookie or header. This allows the attacker to redirect file read operations to arbitrary paths on the system, effectively bypassing authentication checks and granting full administrative access. The issue is resolved in version 0.107.77.
Affected products
- AdGuardTeam AdGuard Home < 0.107.77
Timeline
- 2026-06-02: patched: Version 0.107.77 released
- 2026-06-08: disclosed: CVE published and NVD entry created