{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-0251",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-0251",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2021-04-22T19:37:13.448Z",
    "updatedAt": "2024-09-16T18:56:25.579Z",
    "importedAt": "2026-10-24T01:56:21.187Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "Junos OS: MX Series with MS-PIC, MS-SPC3, MS-MIC or MS-MPC: The BRAS Subscriber Services service activation portal is vulnerable to a Denial of Service (DoS) via malformed HTTP packets",
      "summary": "A NULL Pointer Dereference vulnerability in the Captive Portal Content Delivery (CPCD) services daemon (cpcd) of Juniper Networks Junos OS on MX Series with MS-PIC, MS-SPC3, MS-MIC or MS-MPC allows an attacker to send malformed HTTP packets to the device thereby causing a Denial of Service (DoS), crashing the Multiservices PIC Management Daemon (mspmand) process thereby denying users the ability to login, while concurrently impacting other mspmand services and traffic through the device. Continued receipt and processing of these malformed packets will create a sustained Denial of Service (DoS) condition. While the Services PIC is restarting, all PIC services will be bypassed until the Services PIC completes its boot process. An attacker sending these malformed HTTP packets to the device who is not part of the Captive Portal experience is not able to exploit this issue. This issue is not applicable to MX RE-based CPCD platforms. This issue affects: Juniper Networks Junos OS on MX Series 17.3 version 17.3R1 and later versions prior to 17.4 versions 17.4R2-S9, 17.4R3-S2; 18.1 versions prior to 18.1R3-S9; 18.2 versions prior to 18.2R3-S3; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect: Juniper Networks Junos OS versions prior to 17.3R1.",
      "affected": [
        {
          "vendor": "Juniper Networks",
          "product": "Junos OS",
          "platforms": [
            "MX Series"
          ],
          "versions": [
            {
              "version": "unspecified",
              "status": "unaffected",
              "versionType": "custom",
              "lessThan": "17.3R1"
            },
            {
              "version": "17.3R1",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "17.3*"
            },
            {
              "version": "17.4",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "17.4R2-S9, 17.4R3-S2"
            },
            {
              "version": "18.1",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "18.1R3-S9"
            },
            {
              "version": "18.2",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "18.2R3-S3"
            },
            {
              "version": "18.3",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "18.3R3-S1"
            },
            {
              "version": "18.4",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "18.4R3"
            },
            {
              "version": "19.1",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "19.1R2-S2, 19.1R3"
            },
            {
              "version": "19.2",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "19.2R2"
            },
            {
              "version": "19.3",
              "status": "affected",
              "versionType": "custom",
              "lessThan": "19.3R3"
            }
          ]
        }
      ]
    }
  }
}