# CVE-1999-1387: Microsoft Windows NT denial of service via malformed SMB packets

Source: https://junglewise.ai/threats/cve-1999-1387-microsoft-windows-nt-denial-of-service-via-malformed-smb-packets  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1997-04-02. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-1387 · Severity: medium · CVSS 5 · Published 1997-04-02

A vulnerability in Windows NT 4.0 allows a remote user to crash the server, leading to a Blue Screen of Death (BSoD). This occurs when the server processes specifically malformed network requests during file sharing operations. An attacker with even limited access to a network share can trigger this flaw, causing a complete service outage and requiring a manual reboot of the affected system.

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

## Quick answers

**Is CVE-1999-1387 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-1387 being exploited in the wild.

**How severe is CVE-1999-1387?** Medium severity, with a CVSS score of 5, published 2 April 1997.

**Which products and versions are affected?** Microsoft Windows NT 4.0 Service Pack 2.

**Is there a fix for CVE-1999-1387?** 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-1999-1387 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-1999-1387?** Check whether you run 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

A denial of service vulnerability exists in Windows NT 4.0 Service Pack 2 due to improper handling of malformed SMB (Server Message Block) packets. The issue is triggered when a remote client, such as a Linux system using an incompatible version of the smbmount utility, sends malformed inputs during a directory listing request (ls) on a mounted share. This results in a kernel-level exception (IRQL_NOT_LESS_OR_EQUAL, STOP 0x0000000A) in ntoskrnl.exe, causing an immediate system crash. The attack requires the ability to reach the SMB service over the network and initiate a connection to a shared resource, even with read-only permissions.

## Affected products

- Microsoft Windows NT 4.0 Service Pack 2

## Timeline

- 1997-04-02: disclosed: Initial report on Bugtraq mailing list
- 1997-04-02: advisory: NVD publication date

## References

- [http://marc.info/?l=bugtraq&m=87602167420731&w=2](http://marc.info/?l=bugtraq&m=87602167420731&w=2)
- [http://marc.info/?l=bugtraq&m=87602167420732&w=2](http://marc.info/?l=bugtraq&m=87602167420732&w=2)
- [http://marc.info/?l=bugtraq&m=87602167420741&w=2](http://marc.info/?l=bugtraq&m=87602167420741&w=2)

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