---
title: "CVE-2026-32136: AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass"
url: https://erroneo.us/security/cve/CVE-2026-32136/
description: "CVE-2026-32136 (github.com/AdguardTeam/AdGuardHome (Go)): AdGuard Home is a network-wide software for blocking ads and tracking. Prior to 0.107.73, an…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-11
date_modified: 2026-03-12
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-32136"
kev: false
cvss: 9.8
epss: 0.00813
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.8% , percentile 57: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 57% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/AdguardTeam/AdGuardHome (Go) < 0.107.73, fixed in 0.107.73 . Check your lockfile, including transitive dependencies.

## What it is

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

- Go `github.com/AdguardTeam/AdGuardHome` < 0.107.73 → fixed: 0.107.73

## Affected products (CVE record)

- AdguardTeam AdGuardHome: < 0.107.73

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.81% probability of exploitation activity in the next 30 days; percentile 57.

## Sources

- [GitHub Advisory GHSA-5fg6-wrq4-w5gh](https://github.com/advisories/GHSA-5fg6-wrq4-w5gh)
- [CVE.org record CVE-2026-32136](https://www.cve.org/CVERecord?id=CVE-2026-32136)
- [NVD entry CVE-2026-32136](https://nvd.nist.gov/vuln/detail/CVE-2026-32136)
- [github.com](https://github.com/AdguardTeam/AdGuardHome/security/advisories/GHSA-5fg6-wrq4-w5gh)

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Source page: https://erroneo.us/security/cve/CVE-2026-32136/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt