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

{
  "id": "846d7af5fea39ebd47612958a8cc6ea40d95bf89ee2ae94cb2b306981b790290",
  "url": "https://www.cve.org/CVERecord?id=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": "cve:CVE-2026-90484",
    "products": [
      {
        "name": {
          "value": "Apache bRPC",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90484",
      "aliases": [
        "CVE-2026-90484"
      ],
      "metrics": [
        {
          "other": {
            "type": "Textual description of severity",
            "content": {
              "text": "moderate"
            }
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "affected": [
        {
          "vendor": "Apache Software Foundation",
          "product": "Apache bRPC",
          "versions": [
            {
              "status": "affected",
              "version": "<= 1.11.0",
              "lessThan": "1.18.0",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:github/apache/brpc",
          "packageName": "apache/brpc",
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T13:39:12.101Z",
      "provider": "cve",
      "references": [
        "https://github.com/apache/brpc/pull/3536",
        "https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "cvssV3_1": {
                  "scope": "UNCHANGED",
                  "version": "3.1",
                  "baseScore": 6.5,
                  "attackVector": "NETWORK",
                  "baseSeverity": "MEDIUM",
                  "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                  "integrityImpact": "NONE",
                  "userInteraction": "NONE",
                  "attackComplexity": "LOW",
                  "availabilityImpact": "HIGH",
                  "privilegesRequired": "LOW",
                  "confidentialityImpact": "NONE"
                }
              },
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-90484",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T13:39:08.583202Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-26T13:39:12.101Z"
            }
          }
        ],
        "cna": {
          "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
          "shortName": "apache",
          "dateUpdated": "2026-10-21T12:19:37.796Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90484",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 307229,
  "published_at": "2026-10-21T12:19:37.796+00:00"
}