Apache bRPC: Null pointer dereference in MySQL reply parser leading to client crash

{
  "id": "00cf1e0e53274df255263eb226f9215a012dc1889573cda0fc2ec7d4616fae04",
  "url": "https://osv.dev/vulnerability/CVE-2026-90484",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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 (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.",
    "evidence": "osv:CVE-2026-90484",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-90484",
      "aliases": [
        "CVE-2026-90484"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/apache/brpc",
              "type": "GIT",
              "events": [
                {
                  "introduced": "04d15c08506c4614e2c373662c53ba4ca7055945"
                },
                {
                  "fixed": "94f1bbd32845a45f0218dfe43e25791252bdcb72"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "<= 1.11.0"
                      },
                      {
                        "fixed": "1.18.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90484.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:46.218259661Z",
      "provider": "osv",
      "references": [
        "https://github.com",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90484.json",
        "https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90484",
        "https://github.com/apache/brpc/pull/3536"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-476"
        ],
        "cna_assigner": "apache",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90484.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90484",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 514393,
  "published_at": "2026-10-21T12:19:37.796+00:00"
}