CVE-2026-32136
AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass
- State
- Published
- Severity
- 9.8 Critical
- Published
- Mar 11, 2026
- Updated
- Mar 12, 2026
- Reserved
- Mar 10, 2026
Description
AdGuard Home is a network-wide software for blocking ads and tracking. Prior to 0.107.73, an unauthenticated remote attacker can bypass all authentication in AdGuardHome by sending an HTTP/1.1 request that requests an upgrade to HTTP/2 cleartext (h2c). Once the upgrade is accepted, the resulting HTTP/2 connection is handled by the inner mux, which has no authentication middleware attached. All subsequent HTTP/2 requests on that connection are processed as fully authenticated, regardless of whether any credentials were provided. This vulnerability is fixed in 0.107.73.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
AdGuardHomeAdguardTeam |
|
References
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