What’s Vulnerable › Vulnerabilities

CVE-2026-45673: Netty: DNS Cache Poisoning due to Predictable PRNG and Default Static Source Port

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-12 · updated 2026-06-17
• Weakness: CWE-330

Description

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's DNS resolver uses a predictable PRNG for generating DNS transaction IDs and defaults to a static UDP source port. This combination reduces the entropy of DNS queries, enabling DNS Cache Poisoning (Kaminsky attack). Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Affected products

• netty: before 4.1.135; from 4.2.0 before 4.2.15 — fixed in 4.1.135, 4.2.15

How to fix

Upgrade to a fixed version: netty 4.1.135, 4.2.15. Check the vendor advisory for mitigations.

References

• https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
• https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
• https://github.com/netty/netty/security/advisories/GHSA-xmv7-r254-6q78

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