CVE-2001-0751

Status: ModifiedHigh (7.5)—💥 Exploit

Cisco switches and routers running CBOS 2.3.8 and earlier use predictable TCP Initial Sequence Numbers (ISN), which allows remote attackers to spoof or hijack TCP connections.

CVSS

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

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 2.61%
Percentile among all scored CVEs: 85
Score date: 10/6/2026

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 — Cbos

CWEs

NVD-CWE-Other

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2001-0751",
  "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": "2001-10-18T04:00:00.000",
  "references": [
    {
      "url": "http://www.cisco.com/warp/public/707/CBOS-multiple2-pub.html",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/139",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.cisco.com/warp/public/707/CBOS-multiple2-pub.html",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/139",
      "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 CBOS 2.3.8 and earlier use predictable TCP Initial Sequence Numbers (ISN), which allows remote attackers to spoof or hijack TCP connections."
    },
    {
      "lang": "es",
      "value": "Conmutadores y routers Cisco corriendo CBOS 2.3.8 usan números iniciales de secuencia TCP (ISN) predecibles, lo que permite a un atacante remoto secuestrar o falsificar conexiones TCP;"
    }
  ],
  "lastModified": "2026-06-16T21:54:53.430",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:cisco:cbos:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6E02E785-40FF-4F46-BB32-4D07F08352D2",
              "versionEndIncluding": "2.3.8"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}