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

6.8MEDIUM

Key Information:

Vendor

Netty

Status
Netty
Vendor
CVE Published:
12 June 2026

What is CVE-2026-45673?

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 Version(s)

netty >= 4.2.0.Final, < 4.2.15.Final < 4.2.0.Final, 4.2.15.Final

netty < 4.1.135.Final < 4.1.135.Final

References

https://github.com/netty/netty/security/advisories/GHSA-x...
x_refsource_CONFIRM
https://github.com/netty/netty/releases/tag/netty-4.1.135...
x_refsource_MISC
https://github.com/netty/netty/releases/tag/netty-4.2.15....
x_refsource_MISC

CVSS V3.1

Score:
6.8
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.