CVE-2026-56388 Apache bRPC: Out-of-Bounds Write in Redis Command Parser
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-56388?
CVE-2026-56388 is a vulnerability in Apache bRPC, published on 21 Oct 2026.
Official 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 this patch: https://github.com/apache/brpc/pull/3354
Note: The fix rejects empty RESP arrays as invalid Redis commands and replaces the internal index CHECK with an explicit parse error so malformed command streams cannot fall through to an indexed vector write.
Which versions are affected by CVE-2026-56388?
How do I fix CVE-2026-56388?
No fix has been published for CVE-2026-56388 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-56388 being exploited?
There is no known exploitation of CVE-2026-56388 in the wild and no public exploit code.
Sources
Also known as GHSA-57w6-4hvp-7m4g.