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CVE-1999-0775

Status: ModifiedHigh (10)—
Severity10High · CVSS 2.0
Exploitation probability3.19 %higher than 88% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

Cisco Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the "established" keyword in an access list.

CVSS

Base score
10
Version
2.0
Vector
AV:N/AC:L/Au:N/C:C/I:C/A:C

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
3.19 %
Percentile among all scored CVEs
88
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-1999-0775",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 10,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
          "authentication": "NONE",
          "integrityImpact": "COMPLETE",
          "accessComplexity": "LOW",
          "availabilityImpact": "COMPLETE",
          "confidentialityImpact": "COMPLETE"
        },
        "acInsufInfo": false,
        "impactScore": 10,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": true,
        "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": "1999-06-10T04:00:00.000",
  "references": [
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0775",
      "source": "cve@mitre.org"
    },
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0775",
      "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 Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the \"established\" keyword in an access list."
    }
  ],
  "lastModified": "2026-06-16T21:49:01.957",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:cisco:ios:11.2\\(14\\)gs2:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0023E04A-6244-4221-AE19-616265074BDD"
            },
            {
              "criteria": "cpe:2.3:o:cisco:ios:11.2\\(15\\)g:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "52C4A8A9-A17E-48A1-99EC-A9F87CE17318"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}