Generation of Predictable Numbers or Identifiers Affecting io.netty:netty-resolver-dns package, versions [,4.1.135.Final)[4.2.0.Final,4.2.15.Final)
Threat Intelligence
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-17261131
- published9 Jun 2026
- disclosed8 Jun 2026
- creditVioleta Georgieva
Introduced: 8 Jun 2026
CVE-2026-45673 (opens in a new tab)How to fix?
Upgrade io.netty:netty-resolver-dns to version 4.1.135.Final, 4.2.15.Final or higher.
Overview
Affected versions of this package are vulnerable to Generation of Predictable Numbers or Identifiers due to the use of a predictable pseudo-random number generator for DNS transaction IDs and a default static UDP source port in the DNS resolution process. An attacker can redirect network traffic or perform man-in-the-middle attacks by spoofing DNS responses.
Note:
This is only exploitable if the attacker's forged response arrives before the legitimate DNS reply. The timing window is not guaranteed.