CVE-1999-1577

Exp

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.

Published: 1999-10-31 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-1999-1577 is rated High Exploit Risk (64.4/100): CVSS Medium severity, with high exploitation likelihood (EPSS 19.49%, 97th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-1999-1577

EDB-ID Source Kind Published Link
19521 exploit_db edb 1999-09-27 Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-1999-1577

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 34.94% 19.49% -15.46%
2 2025-12-21 30.69% 34.94% +4.25%
3 2025-04-10 — 30.69% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-1999-1577

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.1 2.0 MEDIUM
AV:N/AC:H/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 4.9 6.4 [email protected]

Weakness enumeration for CVE-1999-1577

Affected software / configurations for CVE-1999-1577

Vendor Product Version Raw CPE
microsoft internet_explorer 4.0.1 cpe:2.3:a:microsoft:internet_explorer:4.0.1:*:*:*:*:*:*:*
microsoft internet_explorer 5.0 cpe:2.3:a:microsoft:internet_explorer:5.0:*:*:*:*:*:*:*

References for CVE-1999-1577

cvelogic Threat Intelligence