# CVE-2026-56388: Apache bRPC: Out-of-Bounds Write in Redis Command Parser


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 21 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-57w6-4hvp-7m4g

## 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.

Weakness: CWE-787 (Out-of-bounds Write), CWE-617 (Reachable Assertion), CWE-252 (Unchecked Return Value)

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56388 and fix it if it is affected.

What it is: CVE-2026-56388 is a vulnerability in Apache bRPC, published on 21 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-56388 in the wild and no public exploit code.

Affected product: Apache bRPC. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-56388/ (Markdown: https://insights.sbomify.com/CVE-2026-56388/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56388
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56388
- OSV: https://osv.dev/vulnerability/CVE-2026-56388

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-56388/
Summaries are generated and may contain mistakes; the official description above is the record.