CVE-2026-56388

/// Technical description

The Redis server command parser in Apache bRPC accepts an empty RESP array as a command header. A remote unauthenticated attacker who can reach a bRPC server with Redis service enabled can send an empty array header followed by a bulk string, causing an out-of-bounds write in the parser and crashing the process.

Root Cause:

RedisCommandParser::ConsumeImpl rejected negative RESP array counts but accepted zero. It resized the command argument vector to zero elements and continued parsing. When a following bulk string was parsed, the only index guard was a CHECK. In configurations where fatal logs do not abort immediately, execution could continue and write to _args[0] even though the vector was empty.

Affected Scenarios:

Deployments that enable ServerOptions.redis_service and accept Redis protocol traffic from untrusted clients. The issue is reached during parsing before command handling or authentication.

How to Fix:

1. Upgrade bRPC to version 1.18.0, which fixes this issue.

2. Apply

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References