CVE-2026-45673 PUBLISHED

Netty: DNS Cache Poisoning due to Predictable PRNG and Default Static Source Port

Assigner: GitHub_M
Reserved: 12.05.2026 Published: 12.06.2026 Updated: 12.06.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
CVSS Score: 6.8

Attack Vector	Network	Scope	Changed
Attack Complexity	High	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	netty
Product	netty
Versions	Version >= 4.2.0.Final, < 4.2.15.Final is affected Version < 4.1.135.Final is affected

References

Problem Types

CWE-330: Use of Insufficiently Random Values CWE
CWE-340: Generation of Predictable Numbers or Identifiers CWE