# CVE-1999-0503: Microsoft Windows NT guessable password for local accounts

Source: https://junglewise.ai/threats/cve-1999-0503-microsoft-windows-nt-guessable-password-for-local-accounts  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1997-01-01. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-0503 · Severity: high · CVSS 7.2 · Published 1997-01-01

Microsoft Windows NT systems are susceptible to unauthorized access because local user or administrator accounts may use weak, easily guessable passwords. An attacker with physical or local access to the machine could gain full control over the system by guessing these credentials. This could lead to the theft of sensitive data, installation of malicious software, or complete disruption of the computer's operations.

Technologies: [Microsoft Windows 2000](https://junglewise.ai/threats/technologies/windows-2000), [Microsoft Windows Nt](https://junglewise.ai/threats/technologies/windows-nt). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-1999-0503 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-0503 being exploited in the wild.

**How severe is CVE-1999-0503?** High severity, with a CVSS score of 7.2, published 1 January 1997.

**Which products and versions are affected?** Microsoft Windows NT.

**Is there a fix for CVE-1999-0503?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-1999-0503 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-1999-0503?** Check whether you run Microsoft Windows 2000 or Microsoft Windows Nt. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability stems from the use of weak or default credentials for local accounts on Microsoft Windows NT. An attacker with local access can perform brute-force or dictionary attacks to guess account passwords. Successful exploitation grants the attacker the privileges associated with the compromised account, which in the case of an administrator account, results in complete control over the operating system (C:C/I:C/A:C). This is a configuration-based weakness rather than a software bug, but it is tracked as a vulnerability due to the high impact of default or easily guessed administrative credentials.

## Affected products

- Microsoft Windows NT

## Timeline

- 1997-01-01: disclosed

## References

- [https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0503](https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0503)

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