# CVE-2026-47703: AdGuard Home: DoQ-to-UDP State Reduction and Source-Port Oracle

> AdGuard Home leaks source port information and weakens DNS response matching, potentially allowing attackers to bypass security controls or gather sensitive data.

- **Severity:** Medium 6.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-xgx4-4h9w-53pv, GO-2026-5756

## What is CVE-2026-47703?

CVE-2026-47703 is a medium-severity vulnerability in AdguardTeam AdGuardHome, published on 15 Jul 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 0.107.75, 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.

Weakness: CWE-346 (Origin Validation Error), CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2026-47703?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/AdguardTeam/AdGuardHome` | Go | All versions | 0.107.75 |
| `github.com/AdguardTeam/AdGuardHome` | Go | All versions | 0.107.75 |
| `github.com/AdguardTeam/AdGuardHome` | Go | All versions | 0.107.75 |
| `github.com/AdguardTeam/dnsproxy` | Go | All versions | 0.81.3 |
| `github.com/AdguardTeam/dnsproxy` | Go | All versions | 0.81.3 |
| `github.com/AdguardTeam/dnsproxy` | Go | All versions | 0.81.3 |

Products: Adguard Adguardhome.

## How do I fix CVE-2026-47703?

Upgrade github.com/AdguardTeam/AdGuardHome to 0.107.75 or later.

## Is CVE-2026-47703 being exploited?

There is no known exploitation of CVE-2026-47703 in the wild and no public exploit code.

## Other vulnerabilities in AdguardTeam AdGuardHome

- [CVE-2026-32136](https://insights.sbomify.com/CVE-2026-32136/): AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass (critical 9.8)
- [CVE-2022-32175](https://insights.sbomify.com/CVE-2022-32175/): AdGuardHome - CSRF (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-47703 and fix it if it is affected.

What it is: CVE-2026-47703 is a medium-severity vulnerability in AdguardTeam AdGuardHome, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-47703 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/AdguardTeam/AdGuardHome (Go): affected all versions; fixed in 0.107.75
- github.com/AdguardTeam/AdGuardHome (Go): affected all versions; fixed in 0.107.75
- github.com/AdguardTeam/AdGuardHome (Go): affected all versions; fixed in 0.107.75
- github.com/AdguardTeam/dnsproxy (Go): affected all versions; fixed in 0.81.3
- github.com/AdguardTeam/dnsproxy (Go): affected all versions; fixed in 0.81.3
- github.com/AdguardTeam/dnsproxy (Go): affected all versions; fixed in 0.81.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-47703/ (Markdown: https://insights.sbomify.com/CVE-2026-47703/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47703
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47703
- OSV: https://osv.dev/vulnerability/CVE-2026-47703

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-47703/
Summaries are generated and may contain mistakes; the official description above is the record.