# CVE-1999-0004: Microsoft Outlook and Solaris mailtool buffer overflow in MIME parsing

Source: https://junglewise.ai/threats/cve-1999-0004-microsoft-outlook-and-solaris-mailtool-buffer-overflow-in-mime  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1997-12-16. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-0004 · Severity: medium · CVSS 5 · Published 1997-12-16

A security vulnerability exists in several older email clients, including Microsoft Outlook and Solaris mailtool, regarding how they process email attachments. If a user receives a message containing an attachment with an extremely long filename, the email application may crash or allow a malicious actor to run unauthorized code on the computer. This could lead to service disruptions or a full compromise of the user's workstation. Patches were released by the respective vendors to address this issue.

Vendors: [Hp](https://junglewise.ai/threats/vendors/hp), [Microsoft](https://junglewise.ai/threats/vendors/microsoft), [Sco](https://junglewise.ai/threats/vendors/sco), [Sun Microsystems](https://junglewise.ai/threats/vendors/sun-microsystems), [University Of Washington](https://junglewise.ai/threats/vendors/university-of-washington).

## Quick answers

**Is CVE-1999-0004 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-0004 being exploited in the wild.

**How severe is CVE-1999-0004?** Medium severity, with a CVSS score of 5, published 16 December 1997.

**Which products and versions are affected?** Microsoft Outlook 98 Windows 95, 98, NT 4.0; Microsoft Outlook Express 4.x 4.0, 4.01, 4.01 SP1; Sun Microsystems Mailtool All versions prior to patch.

**Is there a fix for CVE-1999-0004?** A patch was published on 1998-08-11: Microsoft released updated patches addressing variants of the vulnerability Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-1999-0004 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-1999-0004?** Check whether you run Hp Dtmail, Microsoft Outlook 98, Microsoft Outlook Express 4.x or one of the others listed at an affected version. 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 buffer overflow vulnerability exists in the MIME parsing component of various email clients, most notably Microsoft Outlook 98, Outlook Express 4.x, and Solaris mailtool. The flaw is triggered when the application processes a file attachment with an excessively long filename. In Outlook 98, the crash can occur automatically during the message download process without user interaction, while in Outlook Express, it typically occurs when a user attempts to open or view the attachment. An attacker can exploit this by sending a specially crafted email, potentially leading to arbitrary code execution or a denial of service (application crash). Microsoft released patches for affected versions in 1998.

## Affected products

- Microsoft Outlook 98 Windows 95, 98, NT 4.0
- Microsoft Outlook Express 4.x 4.0, 4.01, 4.01 SP1
- Solaris mailtool All versions prior to patch

## Timeline

- 1997-12-16: disclosed: Initial disclosure date recorded in NVD
- 1998-07-27: advisory: Microsoft published initial security bulletin MS98-008
- 1998-08-11: patched: Microsoft released updated patches addressing variants of the vulnerability

## References

- [https://docs.microsoft.com/en-us/security-updates/securitybulletins/1998/ms98-008](https://docs.microsoft.com/en-us/security-updates/securitybulletins/1998/ms98-008)

## Related threats

- [University of Washington Pine privilege escalation via lockfile symlink](https://junglewise.ai/threats/cve-1999-1187-university-of-washington-pine-privilege-escalation-via-lockfile)