9.8

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

Analyzed
AliasesGHSA-5fg6-wrq4-w5ghGO-2026-4686
Published 11-03-2026Last modified 12-03-2026

Vulnerability summary

CVE-2026-32136 is a critical (CVSS 9.8) Improper Authentication vulnerability in adguard adguardhome. EPSS estimates a 0.77% chance of exploitation in the next 30 days, higher than 55.4% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Prioritisepublic exploit

Public exploit (GitHub, Date unknown)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.77%
0%100%
Low · -0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:1042-1

Timeline

  1. 11-03-2026
    PublishedVulnerability first disclosed.
  2. 12-03-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.77%

Chance of exploitation in the next 30 days

Percentile

55%

Versus all other CVEs

30-day change

Decrease -0.02 pp

From 0.78% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Adguardhome

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Adguard1 product
Adguardteam1 product
Github.com/AdguardTeam1 product
  • AdGuardHome< 0.107.73

3 vendors · 3 products

References

3 links