Improper Synchronization Affecting github.com/adguardteam/dnsproxy/upstream package, versions <0.81.3
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMADGUARDTEAMDNSPROXYUPSTREAM-17231949
- published8 Jun 2026
- disclosed4 Jun 2026
- creditN0zoM1z0
Introduced: 4 Jun 2026
CVE-2026-47703 (opens in a new tab)How to fix?
Upgrade github.com/AdguardTeam/dnsproxy/upstream to version 0.81.3 or higher.
Overview
Affected versions of this package are vulnerable to Improper Synchronization in the process that forwards DoQ queries to UDP upstreams, where the DNS transaction ID (txid) is not preserved and is always set to 0, reducing entropy in the backend tuple. An attacker can increase the likelihood of successfully forging DNS responses or steering queries by exploiting the predictable state and using an oracle to determine the correct UDP source port.