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Vulnerability record · CVE-1999-1577 · published 31 October 1999

CVE-1999-1577: Microsoft internet explorer vulnerability

Microsoft · Internet Explorer

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.

5.1 CVSS 2.0 Medium EPSS 19% · top 2.7%
5.1CVSS 2.0 base score
19%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
16 Jun 2026Last modified by NVD

Description

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.

AV:N/AC:H/Au:N/C:P/I:P/A:P

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.kb.cert.org/vuls/id/29795 US Government Resource
http://www.securityfocus.com/archive/1/28719
http://www.securityfocus.com/bid/669
https://exchange.xforce.ibmcloud.com/vulnerabilities/3314
http://www.kb.cert.org/vuls/id/29795 US Government Resource
http://www.securityfocus.com/archive/1/28719
http://www.securityfocus.com/bid/669
https://exchange.xforce.ibmcloud.com/vulnerabilities/3314

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-1999-1577), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.