CVE-2026-93572

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:

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