Vulnerability Description
Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.136.Final and 4.2.16.Final, Netty's HAProxy encoder ( HAProxyMessageEncoder ) writes AF_UNIX source and destination socket addresses into the HAProxy V1 text protocol without validating them for CRLF characters, so an attacker who controls an AF_UNIX address can inject \r\n sequences and split the single PROXY header into multiple lines. This is possible because the V1 protocol uses CRLF as its line terminator and, unlike IPv4/IPv6 addresses whose format checks implicitly reject CRLF, AF_UNIX addresses are only validated for length (up to 108 bytes), allowing a forged second PROXY header line that spoofs the client source/destination IP to a downstream server or load balancer. The issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | < 4.1.136 |
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/security/advisories/GHSA-wh89-7897-x99hExploitVendor Advisory
- https://github.com/netty/netty/security/advisories/GHSA-wh89-7897-x99hExploitVendor Advisory
FAQ
What is CVE-2026-59919?
CVE-2026-59919 is a vulnerability with a CVSS score of 5.5 (MEDIUM). Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.136.Final and 4.2.16.Final, Netty's HAProxy encoder ( HAProxyMessageEncoder ) writes AF_UNIX source and d...
How severe is CVE-2026-59919?
CVE-2026-59919 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59919?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.