CVE-2026-48059

Summary

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.

Affected Software

VendorProductVersion RangeStatus
nettynetty>= 4.2.0.Final, < 4.2.15.Finalaffected
nettynetty< 4.1.135.Finalaffected

Weaknesses

  • CWE-401: CWE-401: Missing Release of Memory after Effective Lifetime

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

netty-codec-haproxy: Netty HAProxy PROXY protocol v2 codec: Denial of Service via memory leak from crafted PROXY protocol headers

Additional References

References