Vulnerability · Published Mar 11, 2026 · Assigned by GitHub_M
CVE-2026-32136AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass
Critical 9.8
In plain English
A critical-severity improper authentication in AdGuardHome from AdguardTeam. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 58% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/AdguardTeam/AdGuardHome | 0.107.73 | GHSA-5fg6-wrq4-w5gh |
| Go | github.com/AdguardTeam/AdGuardHome | 0.107.73 | GO-2026-4686 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| AdguardTeam | AdGuardHome | < 0.107.73 |
Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H