# CVE-1999-0144: qmail qmail-smtpd denial of service via RCPT memory exhaustion

Source: https://junglewise.ai/threats/cve-1999-0144-qmail-qmail-smtpd-denial-of-service-via-rcpt-memory-exhaustion  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1997-06-01. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-0144 · Severity: low · CVSS 2.1 · Published 1997-06-01

qmail is a widely used mail transfer agent for routing and delivering email. A vulnerability exists where the software does not limit the number of recipients specified in a single email transaction, allowing an attacker to consume all available system memory. This can lead to a complete system crash or service outage, preventing the organization from sending or receiving legitimate email.

Technologies: [Qmail Project Qmail](https://junglewise.ai/threats/technologies/qmail). Vendors: [Qmail Project](https://junglewise.ai/threats/vendors/qmail-project).

## Quick answers

**Is CVE-1999-0144 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-0144 being exploited in the wild.

**How severe is CVE-1999-0144?** Low severity, with a CVSS score of 2.1, published 1 June 1997.

**Which products and versions are affected?** qmail_project qmail All versions prior to June 1997.

**Is there a fix for CVE-1999-0144?** 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-1999-0144 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-1999-0144?** Check whether you run Qmail Project Qmail. 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 qmail-smtpd component fails to impose a configurable upper bound on the number of RCPT commands processed during a single SMTP session. By sending an unlimited stream of recipient addresses, a remote attacker can trigger dynamic memory allocation that eventually exhausts available swap space or physical memory. This is a resource exhaustion vulnerability (CWE-400) that results in a denial of service. While the vendor argued that system-level resource limits (rlimits) should mitigate this, the lack of application-level bounds allows for trivial exploitation on default configurations.

## Affected products

- qmail_project qmail All versions prior to June 1997

## Timeline

- 1997-06-01: disclosed: Initial discovery and public discussion by Wietse Venema
- 1997-06-01: advisory: NVD publication date

## References

- [http://cr.yp.to/qmail/venema.html](http://cr.yp.to/qmail/venema.html)
- [http://marc.info/?l=bugtraq&m=87602558319024&w=2](http://marc.info/?l=bugtraq&m=87602558319024&w=2)
- [http://marc.info/?l=bugtraq&m=87602558319029&w=2](http://marc.info/?l=bugtraq&m=87602558319029&w=2)
- [http://www.ornl.gov/its/archives/mailing-lists/qmail/1997/06/threads.html](http://www.ornl.gov/its/archives/mailing-lists/qmail/1997/06/threads.html)
- [http://www.securityfocus.com/bid/2237](http://www.securityfocus.com/bid/2237)
- [https://exchange.xforce.ibmcloud.com/vulnerabilities/208](https://exchange.xforce.ibmcloud.com/vulnerabilities/208)