Wazuh: Heap-based NULL WRITE Buffer Underflow in GetAlertData

{
  "id": "9f0da9cadf52f6470f466d1f7fa7829d160efffd9294a278d8a3a9d438e1be93",
  "url": "https://osv.dev/vulnerability/CVE-2026-26204",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Wazuh: Heap-based NULL WRITE Buffer Underflow in GetAlertData",
    "summary": "Wazuh is a free and open source platform used for threat prevention, detection, and response. From version 1.0.0 to before version 4.14.4, a heap-based out-of-bounds WRITE occurs in GetAlertData, resulting in writing a NULL byte exactly 1 byte before the start of the buffer allocated by strdup. Due to unsigned integer underflow and pointer arithmetic wrapping, the write lands at offset -1 from the buffer, corrupting heap metadata. A malicious actor can potentially leverage this issue through a compromised agent to cause denial of service or heap corruption by injecting a specially crafted alert into the alerts log file monitored by wazuh-logcollector. This issue has been patched in version 4.14.4.",
    "evidence": "osv:CVE-2026-26204",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-26204",
      "aliases": [
        "CVE-2026-26204",
        "GHSA-j4c7-hwjw-8857"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wazuh/wazuh",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5933ec9ebee76fb2546e5f7fc9f3a27d0aeca605"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.0.0"
                      },
                      {
                        "fixed": "4.14.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5933ec9ebee76fb2546e5f7fc9f3a27d0aeca605"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v4.14.4"
                  },
                  {
                    "cpe": "cpe:2.3:a:wazuh:wazuh:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.0.0"
                      },
                      {
                        "fixed": "4.14.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.14.4-rc1",
            "coverity-w10-4.14.4",
            "coverity-w9-4.14.4",
            "v4.14.1",
            "v4.14.3-rc1",
            "v3.13.1",
            "v3.13.0",
            "v3.12.0",
            "v3.8.0",
            "v3.7.0",
            "v3.6.1",
            "v3.6.0",
            "v3.5.0",
            "v3.2.0",
            "v3.1.0",
            "v2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-26204.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.653693296Z",
      "provider": "osv",
      "references": [
        "https://github.com/wazuh/wazuh/releases/tag/v4.14.4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26204.json",
        "https://github.com/wazuh/wazuh/security/advisories/GHSA-j4c7-hwjw-8857",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-26204"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-124",
          "CWE-191"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26204.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-26204",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 487672,
  "published_at": "2026-04-29T17:43:44.911+00:00"
}