{
  "id": "CVE-2025-53521",
  "url": "https://spydr.io/cve/CVE-2025-53521",
  "published": "2025-10-15T14:15:48.377Z",
  "modified": "2026-06-17T09:38:22.483Z",
  "score": 9.3,
  "severity": "critical",
  "cvss_version": "4.0",
  "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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",
  "score_source": "f5.com",
  "epss": 0.02295,
  "epss_percentile": 0.82673,
  "exploited": true,
  "kev": {
    "added": "2026-03-27",
    "due": "2026-03-30",
    "action": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
    "ransomware": "Unknown",
    "name": "F5 BIG-IP Stack-Based Buffer Overflow Vulnerability",
    "notes": "Please adhere to F5’s guidelines to assess exposure and mitigate risks. Check for signs of potential compromise on all internet accessible F5 products affected by this vulnerability. For more information please see: https://my.f5.com/manage/s/article/K000156741 ; https://my.f5.com/manage/s/article/K000160486 ; https://my.f5.com/manage/s/article/K11438344 ; https://nvd.nist.gov/vuln/detail/CVE-2025-53521"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "F5"
  ],
  "products": [
    "F5 BIG-IP"
  ],
  "cwes": [
    "CWE-121"
  ],
  "description": "When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE). Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.",
  "status": "Analyzed",
  "score_type": "Secondary",
  "scores": {
    "cvss_v40": 9.3,
    "cvss_v31": 9.8,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://my.f5.com/manage/s/article/K000156741",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53521",
      "tags": [
        "US Government Resource"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2025-53521",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}