CVE-1999-0063

Status: ModifiedMedium (5)—Exploit

Severity5Medium · CVSS 2.0

Exploitation probability8.25 %higher than 95% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitAvailablePublished on Exploit-DB

Cisco IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port.

CVSS

Base score: 5
Version: 2.0
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 8.25 %
Percentile among all scored CVEs: 95
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 · Cisco IOS 12.0.2 - Syslog Crash (1/11/1999)

Affected technologies (1)

Cisco — IOS

CWEs

NVD-CWE-Other

References

Show 2 references

Raw JSON (NVD)

Show

{
  "id": "CVE-1999-0063",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "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": "1999-01-11T05:00:00.000",
  "references": [
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0063",
      "source": "cve@mitre.org"
    },
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0063",
      "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 IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port."
    }
  ],
  "lastModified": "2026-06-16T21:47:29.447",
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  "sourceIdentifier": "cve@mitre.org"
}