CVE-2026-63387 affecting package libtevent 0.14.1-1

{
  "id": "db5c8ebdab8c868864991d6fe9a1cacb8ded42185478962ac0ac3cf4e8074236",
  "url": "https://osv.dev/vulnerability/AZL-96918",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-63387 affecting package libtevent 0.14.1-1",
    "summary": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_request_format_response. The final-label check permits j plus label_len plus one to equal buf_len, after which the terminating null byte is written to buf[buf_len]. A crafted DNS server response containing PTR, CNAME, MX, NS, or SOA data can trigger the one-byte out-of-bounds write and crash or corrupt the process. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.",
    "evidence": "osv:AZL-96918",
    "products": [
      {
        "name": {
          "value": "libtevent",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "AZL-96918",
      "aliases": [
        "AZL-96918"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "0.14.1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "libtevent",
            "purl": "pkg:rpm/azure-linux/libtevent",
            "ecosystem": "Azure Linux:3"
          },
          "database_specific": {
            "source": "https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-96918.json"
          }
        }
      ],
      "modified": "2026-10-22T05:37:13Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-63387"
      ],
      "references": [
        "https://nvd.nist.gov/vuln/detail/CVE-2026-63387"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-63387",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 404541,
  "published_at": "2026-08-20T18:16:36+00:00"
}