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Critical

Security advisory

Type: advisorySources: OSVCVE: CVE-2020-28017

Exim 4 before 4.94.2 allows Integer Overflow to Buffer Overflow in receive_add_recipient via an e-mail message with fifty million recipients. NOTE: remote exploitation may be difficult because of resource consumption.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2020-28017
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 06:40 UTC · Revision 1

Source evidence

CVE-2020-28017

core-osv · Original source

Published 6 May 2021, 13:15 UTC

Exim 4 before 4.94.2 allows Integer Overflow to Buffer Overflow in receive_add_recipient via an e-mail message with fifty million recipients. NOTE: remote exploitation may be difficult because of resource consumption.

osv:CVE-2020-28017
Complete source record
{
  "id": "333c7041e6942ab0af2bbb7344464dbc255f276a044b22b6343618150447a07d",
  "url": "https://osv.dev/vulnerability/CVE-2020-28017",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-28017",
    "summary": "Exim 4 before 4.94.2 allows Integer Overflow to Buffer Overflow in receive_add_recipient via an e-mail message with fifty million recipients. NOTE: remote exploitation may be difficult because of resource consumption.",
    "evidence": "osv:CVE-2020-28017",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2020-28017",
      "aliases": [
        "CVE-2020-28017"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/exim/exim",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6429b0fc79595f120703c022ae99aa10d698f909"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.94.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "exim-4.94",
            "exim-4.94-RC2",
            "exim-4.94-RC1",
            "exim-4_94_RC0",
            "exim-4.93",
            "exim-4.93-RC7",
            "exim-4.93-RC6",
            "exim-4.93-RC5",
            "exim-4.93-RC4",
            "exim-4.93-RC3",
            "exim-4.93-RC2",
            "exim-4.93-RC1",
            "exim-4.93-RC0",
            "exim-4.92-jgh",
            "exim-4.92-RC6",
            "exim-4.92",
            "exim-4.92-RC5",
            "exim-4.92-RC4",
            "exim-4.92-RC3",
            "exim-4.92-RC2",
            "exim-4.92-RC1",
            "exim-4_91",
            "exim-4_91_RC4",
            "exim-4_91_RC3",
            "exim-4_91_RC2",
            "exim-4_91_RC1",
            "exim-4_90_RC4",
            "exim-4_90",
            "exim-4_90_RC3",
            "exim-4_90_RC2",
            "exim-4_90_RC1",
            "exim-4.90devstart",
            "exim-4_89_RC3",
            "exim-4_89_RC1",
            "exim-4_88",
            "exim-4_87",
            "exim-4_88_RC6",
            "exim-4_88_RC5",
            "exim-4_88_RC4",
            "exim-4_88_RC3",
            "exim-4_88_RC2",
            "exim-4_88_RC1",
            "exim-4_87_RC7",
            "exim-4_87_RC6",
            "exim-4_87_RC5",
            "exim-4_87_RC4",
            "exim-4_84",
            "exim-4_86",
            "exim-4_85",
            "exim-4_87_RC3",
            "exim-4_87_RC2",
            "exim-4_87_RC1",
            "exim-4_86_RC5",
            "exim-4_86_RC4",
            "exim-4_86_RC3",
            "exim-4_86_RC2",
            "exim-4_86_RC1",
            "exim-4_85_RC4",
            "exim-4_85_RC3",
            "exim-4_85_RC2",
            "exim-4_85_RC1",
            "exim-4_84_RC2",
            "exim-4_84_RC1",
            "exim-4_83",
            "exim-4_83_RC3",
            "exim-4_83_RC2",
            "exim-4_83_RC1",
            "exim-4_82",
            "exim-4_82_RC5",
            "exim-4_82_RC4",
            "exim-4_82_RC3",
            "exim-4_82_RC2",
            "exim-4_82_RC1",
            "exim-4_80",
            "exim-4_80_RC7",
            "exim-4_80_RC6",
            "exim-4_80_RC5",
            "exim-4_80_RC4",
            "exim-4_80_RC3",
            "exim-4_80_RC2",
            "exim-4_80_RC1",
            "exim-4_77",
            "exim-4_77_RC4",
            "exim-4_77_RC3",
            "exim-4_77_RC2",
            "exim-4_77_RC1",
            "exim-4_76",
            "exim-4_76_RC2",
            "exim-4_76_RC1",
            "exim-4_75",
            "exim-4_75_RC3",
            "exim-4_75_RC2",
            "exim-4_75_RC1",
            "exim-4_74",
            "exim-4_74_RC1",
            "exim-4_73",
            "exim-4_73_RC1",
            "exim-4_73_RC00",
            "exim-4_72",
            "exim-4_72_RC2",
            "exim-4_72_RC1",
            "exim-4_71",
            "exim-4_70",
            "exim-4_70_RC4",
            "exim-4_70_RC3",
            "DEVEL_PDKIM_START",
            "exim-4_69",
            "exim-4_68",
            "exim-4_67",
            "exim-4_66",
            "exim-4_65",
            "exim-4_64",
            "exim-4_63",
            "exim-4_62",
            "exim-4_61",
            "exim-4_54",
            "exim-4_53",
            "exim-4_52",
            "exim-4_51",
            "exim-4_50"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-28017.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:42.919531682Z",
      "provider": "osv",
      "references": [
        "https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28017-RCPTL.txt"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-28017",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 435497,
  "published_at": "2021-05-06T13:15:09.533+00:00"
}