CVE-2001-0288

Status: ModifiedHigh (7.5)—Exploit

Severity7.5High · CVSS 2.0

Exploitation probability5.41 %higher than 93% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitAvailablePublished on Exploit-DB

Cisco switches and routers running IOS 12.1 and earlier produce predictable TCP Initial Sequence Numbers (ISNs), which allows remote attackers to spoof or hijack TCP connections.

CVSS

Base score: 7.5
Version: 2.0
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 5.41 %
Percentile among all scored CVEs: 93
Score date: 10/20/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

Published on Exploit-DB · Linux Kernel 2.2 - Predictable TCP Initial Sequence Number (9/27/1999)

Affected technologies (1)

Cisco — IOS

CWEs

NVD-CWE-Other

References

Show 2 references

Raw JSON (NVD)

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{
  "id": "CVE-2001-0288",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 7.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2001-05-03T04:00:00.000",
  "references": [
    {
      "url": "http://www.cisco.com/warp/public/707/ios-tcp-isn-random-pub.shtml",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.cisco.com/warp/public/707/ios-tcp-isn-random-pub.shtml",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-Other"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Cisco switches and routers running IOS 12.1 and earlier produce predictable TCP Initial Sequence Numbers (ISNs), which allows remote attackers to spoof or hijack TCP connections."
    }
  ],
  "lastModified": "2026-06-16T21:54:02.057",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "894D4548-112B-466D-9D16-0D125A078A1E",
              "versionEndIncluding": "12.1"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}