{
  "cveId": "CVE-2023-51766",
  "url": "https://patchblox.com/security/cve/CVE-2023-51766",
  "summary": "CVE-2023-51766 is fixed in 6 products on 1 platform, first by exim4 4.90.1-1ubuntu1.10\u002Besm3, released December 23, 2023. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "exim4: Exim before 4.97.1 allows SMTP smuggling in certain PIPELINING/CHUNKING configurations",
  "description": "Exim before 4.97.1 allows SMTP smuggling in certain PIPELINING/CHUNKING configurations. 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 Exim supports \u003CLF\u003E.\u003CCR\u003E\u003CLF\u003E but some other popular e-mail servers do not.",
  "published": "2023-12-23T22:15:00Z",
  "severity": "medium",
  "cvss": 5.3,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
  "epss": 0.01102,
  "epssPercentile": 0.6593,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Debian 11.6 (bullseye)",
      "fixedVersion": "4.94.2-7\u002Bdeb11u2",
      "fix": "DSA-5597-1",
      "url": "https://patchblox.com/security/fix/linux/dsa-5597-1",
      "released": "2024-01-04T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "4.96-15\u002Bdeb12u4",
      "fix": "DSA-5597-1",
      "url": "https://patchblox.com/security/fix/linux/dsa-5597-1",
      "released": "2024-01-04T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "4.97-3",
      "fix": "DEBIAN-CVE-2023-51766",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-51766",
      "released": "2023-12-24T06:15:07Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Debian 14",
      "fixedVersion": "4.97-3",
      "fix": "DEBIAN-CVE-2023-51766",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-51766",
      "released": "2023-12-24T06:15:07Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "4.90.1-1ubuntu1.10\u002Besm3",
      "fix": "exim4 4.90.1-1ubuntu1.10\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-exim4-4.90.1-1ubuntu1.10-esm3",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.93-13ubuntu1.10",
      "fix": "exim4 4.93-13ubuntu1.10",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-exim4-4.93-13ubuntu1.10",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "4.95-4ubuntu2.5",
      "fix": "exim4 4.95-4ubuntu2.5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-exim4-4.95-4ubuntu2.5",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "4.97-3",
      "fix": "exim4 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-exim4-4.97-3",
      "released": "2026-01-16T01:42:23Z"
    },
    {
      "platform": "linux",
      "product": "exim4",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "4.97-3",
      "fix": "exim4 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-exim4-4.97-3",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "exim4-base",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "4.90.1-1ubuntu1.10\u002Besm3",
      "fix": "exim4-base 4.90.1-1ubuntu1.10\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-exim4-base-4.90.1-1ubuntu1.10-esm3",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-base",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.93-13ubuntu1.10",
      "fix": "exim4-base 4.93-13ubuntu1.10",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-exim4-base-4.93-13ubuntu1.10",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-base",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "4.95-4ubuntu2.5",
      "fix": "exim4-base 4.95-4ubuntu2.5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-exim4-base-4.95-4ubuntu2.5",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-base",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-base 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-exim4-base-4.97-3",
      "released": "2026-01-16T01:42:23Z"
    },
    {
      "platform": "linux",
      "product": "exim4-base",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-base 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-exim4-base-4.97-3",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "exim4-config",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "4.90.1-1ubuntu1.10\u002Besm3",
      "fix": "exim4-config 4.90.1-1ubuntu1.10\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-exim4-config-4.90.1-1ubuntu1.10-esm3",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-config",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.93-13ubuntu1.10",
      "fix": "exim4-config 4.93-13ubuntu1.10",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-exim4-config-4.93-13ubuntu1.10",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-config",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "4.95-4ubuntu2.5",
      "fix": "exim4-config 4.95-4ubuntu2.5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-exim4-config-4.95-4ubuntu2.5",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-config",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-config 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-exim4-config-4.97-3",
      "released": "2026-01-16T01:42:23Z"
    },
    {
      "platform": "linux",
      "product": "exim4-config",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-config 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-exim4-config-4.97-3",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-heavy",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "4.90.1-1ubuntu1.10\u002Besm3",
      "fix": "exim4-daemon-heavy 4.90.1-1ubuntu1.10\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-exim4-daemon-heavy-4.90.1-1ubuntu1.10-esm3",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-heavy",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.93-13ubuntu1.10",
      "fix": "exim4-daemon-heavy 4.93-13ubuntu1.10",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-exim4-daemon-heavy-4.93-13ubuntu1.10",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-heavy",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "4.95-4ubuntu2.5",
      "fix": "exim4-daemon-heavy 4.95-4ubuntu2.5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-exim4-daemon-heavy-4.95-4ubuntu2.5",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-heavy",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-daemon-heavy 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-exim4-daemon-heavy-4.97-3",
      "released": "2026-01-16T01:42:23Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-heavy",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-daemon-heavy 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-exim4-daemon-heavy-4.97-3",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-light",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "4.90.1-1ubuntu1.10\u002Besm3",
      "fix": "exim4-daemon-light 4.90.1-1ubuntu1.10\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-exim4-daemon-light-4.90.1-1ubuntu1.10-esm3",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-light",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.93-13ubuntu1.10",
      "fix": "exim4-daemon-light 4.93-13ubuntu1.10",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-exim4-daemon-light-4.93-13ubuntu1.10",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-light",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "4.95-4ubuntu2.5",
      "fix": "exim4-daemon-light 4.95-4ubuntu2.5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-exim4-daemon-light-4.95-4ubuntu2.5",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-light",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-daemon-light 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-exim4-daemon-light-4.97-3",
      "released": "2026-01-16T01:42:23Z"
    },
    {
      "platform": "linux",
      "product": "exim4-daemon-light",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "4.97-3",
      "fix": "exim4-daemon-light 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-exim4-daemon-light-4.97-3",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "eximon4",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "4.90.1-1ubuntu1.10\u002Besm3",
      "fix": "eximon4 4.90.1-1ubuntu1.10\u002Besm3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-eximon4-4.90.1-1ubuntu1.10-esm3",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "eximon4",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "4.93-13ubuntu1.10",
      "fix": "eximon4 4.93-13ubuntu1.10",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-eximon4-4.93-13ubuntu1.10",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "eximon4",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "4.95-4ubuntu2.5",
      "fix": "eximon4 4.95-4ubuntu2.5",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-eximon4-4.95-4ubuntu2.5",
      "released": "2023-12-23T22:15:00Z"
    },
    {
      "platform": "linux",
      "product": "eximon4",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "4.97-3",
      "fix": "eximon4 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-eximon4-4.97-3",
      "released": "2026-01-16T01:42:23Z"
    },
    {
      "platform": "linux",
      "product": "eximon4",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "4.97-3",
      "fix": "eximon4 4.97-3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-eximon4-4.97-3",
      "released": "2026-01-16T01:42:24Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T07:25:28Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}