# CVE-2026-90484: Apache bRPC: Null pointer dereference in MySQL reply parser leading to client crash


- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 21 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** GHSA-rf6j-677g-5547

## What is CVE-2026-90484?

CVE-2026-90484 is a medium-severity vulnerability in Apache bRPC, published on 21 Oct 2026. 

### Official description

The MySQL client response parser in Apache bRPC dereferences a null pointer when the server peer sends a zero-payload-length response packet. A response packet whose declared payload length is zero is accepted by the frame-length check (is_full_package), after which the parser reads the response type byte via an unbounded 5-byte fetch that returns nullptr, and type = p[4] dereferences it, crashing the client process.

Root Cause: In brpc::policy::MysqlReply::ConsumePartialIOBuf, buf.fetch(header, 5) returns nullptr when the buffered data only holds the 4-byte header of a zero-length packet, then the code reads p[4] (and, in the fast-auth path, p2[4]) without checking for a null or zero-length packet.

Affected Scenarios: A brpc MySQL client connecting to a malicious or compromised MySQL server (or a MITM) can be crashed by a zero-length server response packet, resulting in denial of service of the client.

Fix: The fix rejects zero-length response packets (returning PARSE_ERROR_ABSOLUTELY_WRONG) both for the initial response type determination and after a fast-auth marker, before reading the type byte. Upgrade to the Apache bRPC version 1.18.0 or apply the PR patch at https://github.com/apache/brpc/pull/3536.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-90484?


## How do I fix CVE-2026-90484?

No fix has been published for CVE-2026-90484 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90484 being exploited?

There is no known exploitation of CVE-2026-90484 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90484 and fix it if it is affected.

What it is: CVE-2026-90484 is a medium-severity vulnerability in Apache bRPC, published on 21 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-90484 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-2026-90484/ (Markdown: https://insights.sbomify.com/CVE-2026-90484/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90484
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90484
- OSV: https://osv.dev/vulnerability/CVE-2026-90484

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90484/
Summaries are generated and may contain mistakes; the official description above is the record.