Security advisory

{
  "id": "c1485932110c528341229954e3b8395ac39f06635515929657c5a9d5346e5c88",
  "url": "https://osv.dev/vulnerability/CVE-2026-27859",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-27859",
    "summary": "A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU time. Use MTA capabilities to limit RFC 2231 MIME parameters in mail messages, or upgrade to fixed version where the processing is limited. No publicly available exploits are known.",
    "evidence": "osv:CVE-2026-27859",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-27859",
      "aliases": [
        "CVE-2026-27859"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/dovecot/core",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c1b22ef978ca72999e254b2f3964b3d32d1a4979"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.4.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.2.20",
            "2.2.20.rc1",
            "2.2.19",
            "2.2.19.rc2",
            "2.2.19.rc1",
            "2.2.18",
            "2.2.17",
            "2.2.17.rc2",
            "2.2.17.rc1",
            "2.2.16",
            "2.2.16.rc1",
            "2.2.15",
            "2.2.14",
            "2.2.14.rc1",
            "2.2.13",
            "2.2.13.rc1",
            "2.2.12",
            "2.2.11",
            "2.2.10",
            "2.2.9",
            "2.2.8",
            "2.2.7",
            "2.2.6",
            "2.2.5",
            "2.2.4",
            "2.2.3",
            "2.2.2",
            "2.2.1",
            "2.2.0",
            "2.2.rc7",
            "2.2.rc6",
            "2.2.rc5",
            "2.2.rc4",
            "2.2.rc3",
            "2.2.rc2",
            "2.2.rc1",
            "2.2.beta2",
            "2.2.beta1",
            "2.2.alpha1",
            "2.1.rc6",
            "2.1.rc5",
            "2.1.rc4",
            "2.1.rc3",
            "2.1.rc2",
            "2.1.rc1",
            "2.1.beta1",
            "2.1.alpha2",
            "2.1.alpha1",
            "2.0.8",
            "2.0.7",
            "2.0.6",
            "2.0.5",
            "2.0.4",
            "2.0.3",
            "2.0.2",
            "2.0.1",
            "2.0.0",
            "2.0.rc6",
            "2.0.rc5",
            "2.0.rc4",
            "2.0.rc3",
            "2.0.rc2",
            "2.0.rc1",
            "2.0.beta6",
            "2.0.beta5",
            "2.0.beta4",
            "2.0.beta3",
            "2.0.beta2",
            "2.0.beta1",
            "2.0.alpha3",
            "2.0.alpha2",
            "2.0.alpha1",
            "1.2.rc1",
            "1.2.beta4",
            "1.2.beta3",
            "1.2.beta2",
            "1.2.beta1",
            "1.2.alpha5",
            "1.2.alpha4",
            "1.2.alpha3",
            "1.2.alpha2",
            "1.2.alpha1",
            "1.1.rc3",
            "1.1.rc2",
            "1.1.rc1",
            "1.1.beta16",
            "1.1.beta14",
            "1.1.beta13",
            "1.1.beta12",
            "1.1.beta11",
            "1.1.beta10",
            "1.1.beta9",
            "1.1.beta8",
            "1.1.beta6",
            "1.1.beta5",
            "1.1.beta4",
            "1.1.beta3",
            "1.1.beta2",
            "1.1.beta1",
            "1.1.alpha6",
            "1.1.alpha5",
            "1.1.alpha4",
            "1.1.alpha2",
            "1.1.alpha1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27859.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.005243401Z",
      "provider": "osv",
      "references": [
        "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27859.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-27859"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400"
        ],
        "cna_assigner": "OX",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "3.0.2"
                  },
                  {
                    "last_affected": "3.1.0"
                  },
                  {
                    "last_affected": "2.4.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27859.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27859",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501183,
  "published_at": "2026-03-27T08:10:22.058+00:00"
}