Executive Summary

CVE-2026-50011 is an unbounded pre-allocation vulnerability in the RedisArrayAggregator component of Netty's Redis codec library. The vulnerability occurs because the aggregator pre-allocates an ArrayList with an initial capacity based on the RESP array length declared in the array header, which is read directly from the network before the actual child messages are processed.

A malicious actor can exploit this by sending a RESP array header with an extremely large declared length, causing the aggregator to attempt to allocate a huge amount of memory. This can lead to resource exhaustion and potential denial-of-service (DoS) conditions.

The root cause is the lack of a configurable maximum limit on array header lengths in RedisArrayAggregator, unlike other parts of the code that enforce limits on bulk string lengths.

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Impact Analysis

This vulnerability can impact you by causing resource exhaustion on systems running vulnerable versions of Netty. Specifically, it can lead to denial-of-service (DoS) conditions by forcing the application to allocate excessive memory based on maliciously crafted network input.

The attack is network-based, has low complexity, requires no privileges or user interaction, and primarily affects the availability of the affected system or service.

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Detection Guidance

This vulnerability can be detected by monitoring network traffic for suspicious Redis RESP array headers that declare unusually large array lengths, which may indicate an attempt to exploit the unbounded pre-allocation in RedisArrayAggregator.

Since the vulnerability involves a malicious RESP array header with a very large declared length, detection can involve capturing and inspecting Redis protocol traffic for abnormal array header sizes.

Commands or tools that can help detect this include using packet capture utilities like tcpdump or Wireshark to filter Redis traffic and analyze RESP array headers.

• Use tcpdump to capture Redis traffic on the default port 6379: tcpdump -i <interface> port 6379 -w redis_traffic.pcap
• Open the capture in Wireshark and filter for Redis protocol messages, then inspect array headers for unusually large declared lengths.
• Alternatively, use Redis protocol parsers or custom scripts to parse logs or traffic and flag RESP array headers with excessively large lengths.

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Mitigation Strategies

The immediate mitigation step is to upgrade Netty to a patched version where this vulnerability is fixed.

• Upgrade to Netty version 4.1.135.Final or later.
• Upgrade to Netty version 4.2.15.Final or later.

These versions include patches that add limits to the array header length pre-allocation in RedisArrayAggregator, preventing resource exhaustion.

Until an upgrade is possible, consider network-level protections such as rate limiting or filtering suspicious Redis traffic to reduce exposure to malicious RESP array headers.

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Compliance Impact

CVE-2026-50011 is a denial-of-service vulnerability caused by unbounded memory allocation in Netty's RedisArrayAggregator. It primarily impacts system availability by enabling resource exhaustion through network-based attacks.

While the vulnerability affects availability, there is no direct information provided about impacts on confidentiality or integrity of data, which are critical factors for compliance with standards like GDPR or HIPAA.

Therefore, based on the available information, this vulnerability could indirectly affect compliance by causing service disruptions, which may impact availability requirements under certain regulations. However, no explicit linkage to compliance violations or data breaches is stated.

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