ubuntu-cve-2023-51764
Vulnerability from osv_ubuntu
Published
2023-12-24 05:15
Modified
2026-04-22 07:45
Summary
Details

Postfix through 3.8.5 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports . but some other popular e-mail servers do not. To prevent attack variants (by always disallowing without ), a different solution is required, such as the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "postfix",
            "binary_version": "2.11.0-1ubuntu1.2+esm3"
          },
          {
            "binary_name": "postfix-cdb",
            "binary_version": "2.11.0-1ubuntu1.2+esm3"
          },
          {
            "binary_name": "postfix-ldap",
            "binary_version": "2.11.0-1ubuntu1.2+esm3"
          },
          {
            "binary_name": "postfix-mysql",
            "binary_version": "2.11.0-1ubuntu1.2+esm3"
          },
          {
            "binary_name": "postfix-pcre",
            "binary_version": "2.11.0-1ubuntu1.2+esm3"
          },
          {
            "binary_name": "postfix-pgsql",
            "binary_version": "2.11.0-1ubuntu1.2+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "postfix",
        "purl": "pkg:deb/ubuntu/postfix@2.11.0-1ubuntu1.2+esm3?arch=source\u0026distro=trusty/esm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.11.0-1ubuntu1.2+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.10.2-1",
        "2.10.2-1build1",
        "2.11.0-1",
        "2.11.0-1ubuntu1",
        "2.11.0-1ubuntu1.2",
        "2.11.0-1ubuntu1.2+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "postfix",
            "binary_version": "3.1.0-3ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-cdb",
            "binary_version": "3.1.0-3ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-ldap",
            "binary_version": "3.1.0-3ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-mysql",
            "binary_version": "3.1.0-3ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-pcre",
            "binary_version": "3.1.0-3ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-pgsql",
            "binary_version": "3.1.0-3ubuntu0.4+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "postfix",
        "purl": "pkg:deb/ubuntu/postfix@3.1.0-3ubuntu0.4+esm3?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.0-3ubuntu0.4+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.11.3-1ubuntu2",
        "2.11.3-1ubuntu3",
        "3.0.4-1ubuntu1",
        "3.0.4-2",
        "3.0.4-3",
        "3.0.4-5",
        "3.0.4-5build1",
        "3.1.0-3",
        "3.1.0-3ubuntu0.1",
        "3.1.0-3ubuntu0.2",
        "3.1.0-3ubuntu0.3",
        "3.1.0-3ubuntu0.4",
        "3.1.0-3ubuntu0.4+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "postfix",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-cdb",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-ldap",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-lmdb",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-mysql",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-pcre",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-pgsql",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          },
          {
            "binary_name": "postfix-sqlite",
            "binary_version": "3.3.0-1ubuntu0.4+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "postfix",
        "purl": "pkg:deb/ubuntu/postfix@3.3.0-1ubuntu0.4+esm3?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.3.0-1ubuntu0.4+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.3-1",
        "3.2.3-1build1",
        "3.2.4-1",
        "3.2.5-1",
        "3.2.5-1build1",
        "3.3.0-1",
        "3.3.0-1ubuntu0.1",
        "3.3.0-1ubuntu0.2",
        "3.3.0-1ubuntu0.3",
        "3.3.0-1ubuntu0.4",
        "3.3.0-1ubuntu0.4+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "postfix",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-cdb",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-ldap",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-lmdb",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-mysql",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-pcre",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-pgsql",
            "binary_version": "3.4.13-0ubuntu1.4"
          },
          {
            "binary_name": "postfix-sqlite",
            "binary_version": "3.4.13-0ubuntu1.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "postfix",
        "purl": "pkg:deb/ubuntu/postfix@3.4.13-0ubuntu1.4?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.4.13-0ubuntu1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.4.5-1ubuntu1",
        "3.4.7-1",
        "3.4.7-2",
        "3.4.8-1",
        "3.4.9-1",
        "3.4.10-1",
        "3.4.10-1ubuntu1",
        "3.4.13-0ubuntu1",
        "3.4.13-0ubuntu1.1",
        "3.4.13-0ubuntu1.2",
        "3.4.13-0ubuntu1.3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "postfix",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-cdb",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-ldap",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-lmdb",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-mysql",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-pcre",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-pgsql",
            "binary_version": "3.6.4-1ubuntu1.3"
          },
          {
            "binary_name": "postfix-sqlite",
            "binary_version": "3.6.4-1ubuntu1.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "postfix",
        "purl": "pkg:deb/ubuntu/postfix@3.6.4-1ubuntu1.3?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.6.4-1ubuntu1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5.6-1ubuntu2",
        "3.5.13-1ubuntu1",
        "3.5.13-1ubuntu2",
        "3.5.13-1ubuntu3",
        "3.6.3-4ubuntu1",
        "3.6.3-5ubuntu1",
        "3.6.3-5ubuntu2",
        "3.6.4-1ubuntu1",
        "3.6.4-1ubuntu1.1",
        "3.6.4-1ubuntu1.2"
      ]
    }
  ],
  "aliases": [],
  "details": "Postfix through 3.8.5 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports \u003cLF\u003e.\u003cCR\u003e\u003cLF\u003e but some other popular e-mail servers do not. To prevent attack variants (by always disallowing \u003cLF\u003e without \u003cCR\u003e), a different solution is required, such as the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.",
  "id": "UBUNTU-CVE-2023-51764",
  "modified": "2026-04-22T07:45:30Z",
  "published": "2023-12-24T05:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2023-51764"
    },
    {
      "type": "REPORT",
      "url": "https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2023/12/21/6"
    },
    {
      "type": "REPORT",
      "url": "https://www.postfix.org/smtp-smuggling.html"
    },
    {
      "type": "REPORT",
      "url": "https://www.mail-archive.com/postfix-users@postfix.org/msg100901.html"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2023/12/22/3"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-6591-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-6591-2"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-51764"
    }
  ],
  "related": [
    "USN-6591-1",
    "USN-6591-2"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2023-51764"
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.