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AdguardhomeApplication · Adguard

CVE-2026-47703

MEDIUM · 5.3 CVSS v3.1 Published 2026-07-15
Fix available
A fix is available. Upgrade to 0.107.75 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
AdGuard Home is a network-wide software for blocking ads and tracking. Prior to 0.107.75, AdGuard Home's client-triggered DoQ forwarding path to a udp:// upstream reduced backend UDP DNS state by producing dns_id=0 or txid=0 and exposed a quoted-port ICMP source-port oracle, weakening DNS response matching for forwarded queries. This issue is fixed in version 0.107.75.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

AdGuard Home versions prior to 0.107.75 have a weakness in the DoQ (DNS over QUIC) to UDP upstream forwarding path. The client-triggered forwarding produces dns_id=0 or txid=0 values in DNS queries, which exposes a quoted-port ICMP source-port oracle. This weakens DNS response matching for forwarded queries, potentially facilitating DNS response manipulation or cache poisoning attacks.

MitigationUpgrade AdGuard Home to version 0.107.75 or later to remediate this vulnerability. Organizations should schedule maintenance windows for the upgrade and verify DNS resolution functionality post-update.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AdguardhomeApplication
Affected:< 0.107.75

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm AdGuard Home is installed
    Check for the presence of AdGuard Home process or service running on the system, or look for AdGuard Home installation directories (commonly /opt/adguardhome or C:\Program Files\AdGuardHome on Windows)
    Affected if AdGuard Home software is found on the system
  2. Identify installed AdGuard Home version
    Run 'adguardhome --version' from the command line if the binary is in PATH, or check the version displayed in the AdGuard Home web interface (usually accessible on port 3000)
    Affected if The version number is lower than 0.107.75 (for example, 0.107.74, 0.107.50, etc.)
  3. Check for DNS over QUIC upstream configuration
    Access AdGuard Home web interface, navigate to DNS Settings, and examine the Upstream DNS servers configuration section for any 'quic://' prefixed DNS server entries
    Affected if DoQ (DNS over QUIC) upstream servers are configured using the 'quic://' protocol
  4. Verify DoQ to UDP forwarding is active
    In the AdGuard Home web interface under DNS settings, check if there are any upstream configurations that route DoQ queries to UDP-based DNS servers, or review the dns.yaml configuration file for upstream definitions
    Affected if DoQ upstream servers are configured and actively being used for DNS resolution

A system is affected if AdGuard Home version is below 0.107.75 AND DoQ (DNS over QUIC) upstream servers are configured and actively forwarding queries to UDP upstreams.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.107.75 or later
Fixed in 0.107.75
Interim mitigation

Upgrade AdGuard Home to version 0.107.75 or later to remediate this vulnerability. Organizations should schedule maintenance windows for the upgrade and verify DNS resolution functionality post-update.

Recommended fix High confidence

version 0.107.75

  1. 1. Check current AdGuard Home version by accessing the dashboard or running 'AdGuardHome --version'
  2. 2. Backup the AdGuard Home configuration (config.yaml) and any custom filter lists
  3. 3. Upgrade AdGuard Home to version 0.107.75 or later
  4. 4. Verify the upgrade was successful by checking the version number
  5. 5. Test DNS resolution to confirm normal operation

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Adguardhome Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,540
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,464.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-47703 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data