Medium severity · published Jun 12, 2026
CVE-2026-45673
Netty: DNS Cache Poisoning due to Predictable PRNG and Default Static Source Port
6.8
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
netty · netty
>= 4.2.0.Final, < 4.2.15.Final; < 4.1.135.Final · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45673
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45673
Release Notes
https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
Release Notes
https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
Vendor Advisory
https://github.com/netty/netty/security/advisories/GHSA-xmv7-r254-6q78
More from netty
7.5
CVE-2023-44487
HTTP/2 Rapid Reset Attack Vulnerability
10.0
CVE-2026-47691
Netty has Insufficient Bailiwick Validation for NS Records
10.0
CVE-2026-45674
Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records
9.8
CVE-2026-56817
Netty: XML External Entity (XXE) injection via unconfigured XML factory when DTD and entity processing are enabled
9.8
CVE-2026-42581
Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization