CVE-2026-55851

CVE-2026-55851 affects Netty (codec-haproxy) where the HAProxyMessageDecoder reads the 13th byte as a signed value and sign-extends to int, causing a PROXY v2 prefix with 0xFF to collide with the decoder’s need-more-data sentinel. This leads to unbounded cumulation and potential memory exhaustion...

CVE-2026-55851 Netty codec-haproxy: Signed-Byte Sentinel Collision in HAProxyMessageDecoder Leads to Unbounded Memory Exhaustion

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final up to but not including 4.2.16.Final, and 4.1.0.Final up to but not including 4.1.135, the HAProxyMessageDecoder in Netty's codec-haproxy module performs protocol version detection by...

CVE-2026-55851 Netty codec-haproxy: Signed-Byte Sentinel Collision in HAProxyMessageDecoder Leads to Unbounded Memory Exhaustion

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final up to but not including 4.2.16.Final, and 4.1.0.Final up to but not including 4.1.135, the HAProxyMessageDecoder in Netty's codec-haproxy module performs protocol version detection by...