CVE-2026-47703

AdGuard Home: DoQ-to-UDP State Reduction and Source-Port Oracle

Published Jul 15, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed

Description

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.

Analysis

Technical impact

AdGuard Home forwards DoQ queries to UDP DNS upstreams; before version 0.107.75 this forwarding strips backend state by sending queries with dns_id or txid set to zero and exposes an ICMP source‑port oracle. The weakened DNS response matching allows attackers to forge or spoof responses and to cause denial‑of‑service through failed validation checks, mapping to CWE‑330 and CWE‑346 weaknesses.

Affected Systems

The flaw affects AdguardTeam’s AdGuard Home product, specifically versions prior to 0.107.75. Upgrading to 0.107.75 or later removes the vulnerability.

Risk and Exploitability

With a CVSS score of 6.3 the risk is moderate, and the EPSS score of less than 1 % indicates a low likelihood of exploitation in the wild. The vulnerability is not listed in CISA’s KEV catalog, suggesting no documented active exploitation yet. The attack likely occurs from a network‑level attacker who can send DoQ queries to the affected AdGuard Home instance; however, this is inferred from the description that the issue resides in the DoQ‑to‑UDP forwarding path.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

AdguardTeam

AdGuardHome

affected

Version	Status	Constraints
`< 0.107.75`	affected	—

Configuration 1 [-]

cpe:2.3:a:adguard:adguardhome:*:*:*:*:*:*:*:*

No data.

Vendor Product Versions

Adguard

Adguardhome

Version	Status	Scheme	Platform
`[0,0.107.75)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade AdGuard Home to version 0.107.75 or later to apply the fix for DoQ-to‑UDP state reduction.
Disable or restrict client‑triggered DoQ forwarding if the feature is not required, reducing exposure to the oracle.
Implement network‑level controls, such as firewall rules, to limit inbound DoQ traffic to trusted IPs only, mitigating potential attacker‑initiated queries.

Generated by OpenCVE AI on July 31, 2026 at 03:24 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-xgx4-4h9w-53pv	AdGuard Home: DoQ-to-UDP State Reduction and Source-Port Oracle

Metrics

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.143% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/AdguardTeam/AdGuardHome/security/advisories/GHSA-xgx4-4h9w-53pv

History

Jul 28, 2026 8:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Adguard Adguard adguardhome
Vendors & Products		Adguard Adguard adguardhome

Jul 15, 2026 6:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jul 15, 2026 4:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		AdGuard Home: DoQ-to-UDP State Reduction and Source-Port Oracle
Weaknesses		CWE-330 CWE-346
References		https://github.com/AdguardTeam/AdGuardHome/security/advisories/GHSA-xgx4-4h9w-53pv
Metrics		cvssV4_0 `{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}`