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CVE-1999-0160

Status: ModifiedHigh (7.5)—
Severity7.5High · CVSS 2.0
Exploitation probability1.22 %higher than 69% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

Some classic Cisco IOS devices have a vulnerability in the PPP CHAP authentication to establish unauthorized PPP 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
1.22 %
Percentile among all scored CVEs
69
Score date
10/23/2026

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).

Affected technologies (1)

Cisco — IOS

CWEs

References

Show 2 references

Raw JSON (NVD)

Show
{
  "id": "CVE-1999-0160",
  "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": true,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "1997-10-01T04:00:00.000",
  "references": [
    {
      "url": "http://www.osvdb.org/1099",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.osvdb.org/1099",
      "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": "Some classic Cisco IOS devices have a vulnerability in the PPP CHAP authentication to establish unauthorized PPP connections."
    }
  ],
  "lastModified": "2026-06-16T21:47:43.793",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:cisco:ios:4.1:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "96C6FB91-22FC-4DA9-B19A-8065D8B89F03"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:9.1:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "2E9A00D5-A594-4C64-B982-10CB4C554F51"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:10.3:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3824A6CC-5C3A-4146-9CDD-B7B213527552"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:11.0:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "D626B494-6210-4F74-8D17-BA480B6665C3"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:11.1:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "82B6315D-7BEF-419F-9B93-3CF669E986D1"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:11.2:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E8026B11-6144-467F-8094-F4F73CD37526"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:11.2p:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0DC1411B-4E7E-4F57-B025-9FE27B09C7AC"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}