Redisson Java Client Resource Exhaustion via Nested RESP Arrays
CVE-2026-93572 Published on September 18, 2026
Netty: netty-codec-redis: io.netty/netty-codec-redis: netty: redisarrayaggregator nested resp headers multiply patched preallocation limits
## Summary
`RedisArrayAggregator` recently added `maxElements` and `maxNestedArrayDepth` limits to fix public Redis resource-exhaustion advisories. The limits are independent, but the allocator remains eager: every positive nested RESP array header creates `new ArrayList<RedisMessage>(length)` before any child element exists.
With the default constructor, an attacker can send nested array headers with length `1,000,000` until the default nesting limit of `1024` is reached. This can reserve up to `1,024,000,000` child slots from roughly 12 KB of RESP input. This is backing capacity, not logical list size: `ArrayList(int)` constructs an empty list with the specified initial capacity.
## Technical Details
Current `decodeRedisArrayHeader(...)` checks the two limits independently:
```java
if (header.length() > maxElements) {
throw new CodecException("this codec doesn't support longer length than " + maxElements);
}
if (depths.size() >= maxNestedArrayDepth) {
releaseAndClearDepths();
throw new CodecException("max nested array depth exceeded: " + maxNestedArrayDepth);
}
depths.push(new AggregateState((int) header.length()));
```
`AggregateState` i
Timeline
Reported to Red Hat.
Made public.
Weakness Type
Allocation of Resources Without Limits or Throttling
The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.
Products Associated with CVE-2026-93572
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