Null Byte Interaction Error (Poison Null Byte) Affecting io.netty:netty-codec-dns package, versions [,4.1.133.Final)[4.2.0.Alpha1,4.2.13.Final)
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-JAVA-IONETTY-16438938
- published7 May 2026
- disclosed7 May 2026
- creditUnknown
Introduced: 7 May 2026
CVE-2026-42579 (opens in a new tab)How to fix?
Upgrade io.netty:netty-codec-dns to version 4.1.133.Final, 4.2.13.Final or higher.
Overview
Affected versions of this package are vulnerable to Null Byte Interaction Error (Poison Null Byte) due to inadequate validation of domain name labels and lengths in the encodeDomainName and decodeDomainName components. An attacker can cause DNS cache poisoning, bypass domain validation, or trigger excessive memory allocation by supplying specially crafted domain names or malicious DNS responses. This can result in downstream failures, silent truncation of domain names, and parser confusion across different DNS implementations.