log4net — security advisory

{
  "id": "27a31f0556cf330d102437a36ba939412377145affe17ab947fd50002b73d2df",
  "url": "https://osv.dev/vulnerability/ECHO-b32c-0992-129e",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ECHO-b32c-0992-129e",
    "summary": "ECHO-b32c-0992-129e",
    "evidence": "osv:ECHO-b32c-0992-129e",
    "products": [
      {
        "name": {
          "value": "log4net",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "3.0.3+echo.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "ECHO-b32c-0992-129e",
      "aliases": [
        "ECHO-b32c-0992-129e"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3.0.3+echo.1"
                }
              ]
            }
          ],
          "package": {
            "name": "log4net",
            "purl": "pkg:nuget/log4net",
            "ecosystem": "Echo:NuGet"
          },
          "database_specific": {
            "source": "https://advisory.echohq.com/osv/ECHO-b32c-0992-129e.json"
          }
        }
      ],
      "modified": "2026-10-20T14:15:03.061415114Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-40021",
        "GHSA-4f7c-pmjv-c25w"
      ],
      "references": [
        "https://advisory.echohq.com/cve/CVE-2026-40021",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-40021",
        "https://github.com/apache/logging-log4net/pull/280",
        "https://lists.apache.org/thread/q8otftjswhk69n3kxslqg7cobr0x4st7",
        "https://logging.apache.org/cyclonedx/vdr.xml",
        "https://logging.apache.org/log4net/manual/configuration/layouts.html",
        "https://logging.apache.org/security.html#CVE-2026-40021",
        "https://github.com/advisories/GHSA-4f7c-pmjv-c25w"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-40021",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 388764,
  "published_at": "2026-10-20T13:58:06.467+00:00"
}