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 RedisArrayAggregator handler permanently leaks pooled direct-memory buffers when a Redis pipeline connection closes before a RESP array aggregate completes. The handler retains child messages in per-handler state (depths field) but defines no channelInactive, handlerRemoved, or exceptionCaught method to release them when the pipeline tears down. Because the leaked buffers are slices of PooledByteBufAllocator chunks, they prevent those chunks from being returned to the JVM-wide direct-memory pool. Repeated connection churn by any network peer monotonically drains this shared pool, eventually causing allocation failures on all Netty channels in the process. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
Weakness
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Netty | Netty | * | 4.1.135 (excluding) |
| Netty | Netty | 4.2.0 (including) | 4.2.15 (excluding) |
Potential Mitigations
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
- For example, glibc in Linux provides protection against free of invalid pointers.
- When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
- To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.