{
  "crds_version": "0.1",
  "kind": "base",
  "id": "crds:cve-2025-21590",
  "revision": 1,
  "title": "Juniper Junos OS — shell access injects code into the kernel",
  "summary": "The kernel in Juniper's router software (Junos OS) does not isolate components properly, so a local attacker with shell access and high privileges injects code and compromises the device's integrity.",
  "source_type": "cve",
  "severity": "medium",
  "cvss": {
    "score": 6.7,
    "vector": "CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
    "version": "4.0"
  },
  "epss": 0.01715,
  "exploitation": {
    "known_exploited": true,
    "exploit_available": false,
    "attack_complexity": "low",
    "kev_added": "2025-03-13",
    "prerequisites": "Local shell access on the device with high privileges."
  },
  "remediation": {
    "patch_available": true
  },
  "kill_chain": "privilege_escalation",
  "recommended_action": "Apply the Juniper fix from JSA93446 now; a China-linked group targets these routers, so restrict shell access and check for unexpected kernel modules.",
  "confidence": "high",
  "provenance": [
    {
      "fields": [
        "cvss",
        "exploitation.attack_complexity",
        "exploitation.exploit_available",
        "references",
        "published_at"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2025-21590",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "exploitation.known_exploited",
        "exploitation.kev_added"
      ],
      "source": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "epss"
      ],
      "source": "https://api.first.org/data/v1/epss?cve=CVE-2025-21590",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "title",
        "summary",
        "severity",
        "remediation",
        "mitre_attack",
        "kill_chain",
        "recommended_action",
        "confidence",
        "tags",
        "exploitation.prerequisites"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2025-21590",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "claude-code"
    }
  ],
  "references": [
    {
      "type": "cve",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21590",
      "label": "NVD record"
    },
    {
      "type": "cisa",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "label": "CISA Known Exploited Vulnerabilities catalog"
    },
    {
      "type": "vendor_advisory",
      "url": "https://supportportal.juniper.net/JSA93446"
    },
    {
      "type": "writeup",
      "url": "https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers"
    }
  ],
  "published_at": "2025-03-12T14:15:15.447Z",
  "issued_at": "2026-09-24T12:03:01.274Z",
  "tags": [
    "juniper",
    "junos",
    "router",
    "privilege-escalation",
    "espionage",
    "kev"
  ]
}