CVE-2026-32136
AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass
CRITICAL 9.8EPSS 0.8%
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.
- Affected
- AdguardTeam · AdGuardHome
- CVSS v3.1 GITHUB
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 0.81% chance of exploitation in the next 30 days, 56th percentile
- Published
- 2026-03-11
- Updated
- 2026-03-12
Proof-of-concept exploits (2)
- advisories/GHSA-5fg6-wrq4-w5gh
- 0xdak/CVE-2026-32136_exploit0★ · 2026-04-27