CVE-2026-32136 AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass

What is CVE-2026-32136?

CVE-2026-32136 is a critical authentication bypass vulnerability in AdguardTeam AdGuardHome, published on 11 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

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.

Weakness: CWE-287

Which versions are affected by CVE-2026-32136?

3 open source packages ship an affected version, including github.com/AdguardTeam/AdGuardHome. It affects 1 product.

Products include Adguard Adguardhome.

How do I fix CVE-2026-32136?

Upgrade github.com/AdguardTeam/AdGuardHome to 0.107.73 or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-32136 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32136 exists.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in AdguardTeam AdGuardHome

• CVE-2026-47703 AdGuard Home: DoQ-to-UDP State Reduction and Source-Port Oracle Medium 6.3
• CVE-2022-32175 AdGuardHome - CSRF Medium 5.4

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-5fg6-wrq4-w5gh, GO-2026-4686.