{
  "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-2025-21594",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-21594",
    "idYear": 2025,
    "status": "PUBLISHED",
    "publishedAt": "2025-04-09T19:49:41.391Z",
    "updatedAt": "2025-04-10T13:14:00.650Z",
    "importedAt": "2026-10-24T01:57:29.455Z",
    "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: In DS-lite and NAT scenario receipt of crafted IPv6 traffic causes port block",
      "summary": "An Improper Check for Unusual or Exceptional Conditions vulnerability in the pfe (packet forwarding engine) of Juniper Networks Junos OS on MX Series causes a port within a pool to be blocked leading to Denial of Service (DoS).\n\nIn a DS-Lite (Dual-Stack Lite) and NAT (Network Address Translation) scenario, when crafted IPv6 traffic is received and prefix-length is set to 56, the ports assigned to the user will not be freed.  Eventually, users cannot establish new connections. Affected FPC/PIC need to be manually restarted to recover.\nFollowing is the command to identify the issue: \n\n\n    user@host> show services nat source port-block \n    Host_IP                       External_IP                    Port_Block      Ports_Used/        Block_State/\n                                                               Range             Ports_Total        Left_Time(s)\n    2001::                        x.x.x.x                     58880-59391     256/256*1         Active/-        >>>>>>>>port still usedThis issue affects Junos OS on MX Series: \n\n  *  from 21.2 before 21.2R3-S8, \n  *  from 21.4 before 21.4R3-S7, \n  *  from 22.1 before 22.1R3-S6, \n  *  from 22.2 before 22.2R3-S4, \n  *  from 22.3 before 22.3R3-S3, \n  *  from 22.4 before 22.4R3-S2, \n  *  from 23.2 before 23.2R2-S1, \n  *  from 23.4 before 23.4R1-S2, 23.4R2.\n\n\nThis issue does not affect versions before 20.2R1.",
      "affected": [
        {
          "vendor": "Juniper Networks",
          "product": "Junos OS",
          "platforms": [
            "MX Series"
          ],
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "21.2R3-S8"
            },
            {
              "version": "21.4",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "21.4R3-S7"
            },
            {
              "version": "22.1",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "22.1R3-S6"
            },
            {
              "version": "22.2",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "22.2R3-S4"
            },
            {
              "version": "22.3",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "22.3R3-S3"
            },
            {
              "version": "22.4",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "22.4R3-S2"
            },
            {
              "version": "23.2",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "23.2R2-S1"
            },
            {
              "version": "23.4",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "23.4R1-S2, 23.4R2"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "20.2R1"
            }
          ]
        }
      ]
    }
  }
}