Security advisory

{
  "id": "379be4bbcca6ac5f4f425ad90edebb63282530c561792bca79e69f02b37686ca",
  "url": "https://osv.dev/vulnerability/CVE-2021-33586",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-33586",
    "summary": "InspIRCd 3.8.0 through 3.9.x before 3.10.0 allows any user (able to connect to the server) to access recently deallocated memory, aka the \"malformed PONG\" issue.",
    "evidence": "osv:CVE-2021-33586",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-33586",
      "aliases": [
        "CVE-2021-33586"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/inspircd/inspircd",
              "type": "GIT",
              "events": [
                {
                  "introduced": "d38595e7e14e7509e744d33df657d50d00cc201f"
                },
                {
                  "fixed": "6ff8f38a6d55970af1400cc78994e017ca351c39"
                },
                {
                  "fixed": "4350a11c663b0d75f8119743bffb7736d87abd4d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:inspircd:inspircd:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.8.0"
                      },
                      {
                        "fixed": "3.10.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4350a11c663b0d75f8119743bffb7736d87abd4d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.9.0",
            "v3.8.1",
            "v3.8.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-33586.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-33586-44bd76ff",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "172236433412257313883103957772383903383",
                    "220703310501416717366140712732379042131",
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                    "263384407924776216272824341098924172406",
                    "315415170026200256221787970084830905795"
                  ]
                },
                "source": "https://github.com/inspircd/inspircd/commit/4350a11c663b0d75f8119743bffb7736d87abd4d",
                "target": {
                  "file": "include/clientprotocolmsg.h"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-33586-6c241bbe",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
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                    "249933969203486859797144565555425798009",
                    "122328167582706218575434760079144219617",
                    "206397735007201542476051935054925026908"
                  ]
                },
                "source": "https://github.com/inspircd/inspircd/commit/4350a11c663b0d75f8119743bffb7736d87abd4d",
                "target": {
                  "file": "src/coremods/core_user/core_user.cpp"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:23:25Z"
          }
        }
      ],
      "modified": "2026-10-20T14:23:25.997644044Z",
      "provider": "osv",
      "references": [
        "https://security.gentoo.org/glsa/202107-22",
        "https://docs.inspircd.org/security/2021-01/",
        "https://github.com/inspircd/inspircd/commit/4350a11c663b0d75f8119743bffb7736d87abd4d"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-33586",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388859,
  "published_at": "2021-05-27T05:15:06.993+00:00"
}