CVE-1999-1577

Status: ModifiedMedium (5.1)—💥 Exploit

Buffer overflow in HHOpen ActiveX control (hhopen.ocx) 1.0.0.1 for Internet Explorer 4.01 and 5 allows remote attackers to execute arbitrary commands via long arguments to the OpenHelp method.

CVSS

Version: 2.0
Vector: AV:N/AC:H/Au:N/C:P/I:P/A:P
Base score: 5.1

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 19%
Percentile among all scored CVEs: 97
Score date: 10/10/2026

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 · Microsoft Internet Explorer 5.0/4.0.1 - hhopen OLE Control Buffer Overflow (9/27/1999)

Affected technologies (1)

Microsoft — Internet Explorer

CWEs

NVD-CWE-Other

References

Raw JSON (NVD)

Show

{
  "id": "CVE-1999-1577",
  "cveTags": [],
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          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:H/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "HIGH",
          "availabilityImpact": "PARTIAL",
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        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
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  "published": "1999-10-31T04:00:00.000",
  "references": [
    {
      "url": "http://www.kb.cert.org/vuls/id/29795",
      "tags": [
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    {
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "description": [
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  "descriptions": [
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      "lang": "en",
      "value": "Buffer overflow in HHOpen ActiveX control (hhopen.ocx) 1.0.0.1 for Internet Explorer 4.01 and 5 allows remote attackers to execute arbitrary commands via long arguments to the OpenHelp method."
    }
  ],
  "lastModified": "2026-06-16T21:50:45.543",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
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}