CVE-2026-48059: netty

Vulnerability summary

CVE-2026-48059 is a high (CVSS 8.7) vulnerability in netty. EPSS estimates a 0.88% chance of exploitation in the next 30 days, higher than 58.4% of scored vulnerabilities.

Timeline

1. 12-06-2026
   PublishedVulnerability first disclosed.
2. 18-09-2026
   Last modifiedVulnerability information updated.

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, the HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

• CWE-401Missing Release of Memory after Effective LifetimeThe product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
• CWE-1286Improper Validation of Syntactic Correctness of InputThe product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.