---
id: CVE-2026-90484
title: >-
  Apache bRPC: Null pointer dereference in MySQL reply parser leading to client
  crash
summary: >-
  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 (…
severity: none
cwe:
  - CWE-476
vendor: Apache Software Foundation
product: apache/brpc
affected:
  - apache/brpc >= <= 1.11.0 < 1.18.0
published: '2026-10-21'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:19:37.796Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-90484'
references:
  - url: 'https://github.com/apache/brpc/pull/3536'
    label: PR 3536
  - url: 'https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb'
tags:
  - cve.org
ingestedAt: '2026-10-21T12:48:53.754Z'
---

## Overview

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.

## Affected

- `apache/brpc >= <= 1.11.0 < 1.18.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.