CVE-2026-46340
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk30th percentile - higher than 30% of all known CVEs
Summary
In Netty library netty-transport-sctp prior to versions 4.1.135.Final and 4.2.15.Final, there is a resource exhaustion vulnerability. For each incomplete SctpMessage fragment, the handler creates a new CompositeByteBuf, leading to recursive buffer nesting. An attacker can send small fragments without the 'complete' flag, causing unlimited growth of the data structure and potential memory exhaustion.
Risk Assessment
The risk is a Denial of Service (DoS) attack by sending small SCTP fragments, leading to server memory exhaustion and service disruption. The vulnerability can be exploited remotely without authentication.
Recommendation
Immediately update Netty to version 4.1.135.Final or 4.2.15.Final, which contain the fix. If update is not possible, consider restricting access to SCTP services or applying firewall rules to block incomplete fragments.
Original NVD description (English source)
Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a *new* CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.