# CVE-1999-0971: Exim buffer overflow in .forward file processing

Source: https://junglewise.ai/threats/cve-1999-0971-exim-buffer-overflow-in-forward-file-processing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1997-07-22. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-0971 · Severity: high · CVSS 7.2 · Published 1997-07-22

A security vulnerability in the Exim mail server allows a local user to take complete control of the underlying server. By placing a specially crafted file in their own directory, a user can trigger a system error that grants them administrative (root) privileges. This could lead to a total compromise of the system's data and operations by any individual with basic access to the machine.

Technologies: [Exim](https://junglewise.ai/threats/technologies/exim). Vendors: [Exim](https://junglewise.ai/threats/vendors/exim).

## Quick answers

**Is CVE-1999-0971 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-0971 being exploited in the wild.

**How severe is CVE-1999-0971?** High severity, with a CVSS score of 7.2, published 22 July 1997.

**Which products and versions are affected?** Exim Exim.

**Is there a fix for CVE-1999-0971?** 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-1999-0971 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-1999-0971?** Check whether you run Exim. 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 Exim mail transfer agent (MTA) during the processing of user-defined .forward files. The flaw is triggered when the software handles an excessively long string within the ':include:' option of the file. Because Exim often runs with high privileges to handle mail delivery, a local attacker can exploit this memory corruption to execute arbitrary code with root authority. This is a local privilege escalation vulnerability requiring the attacker to have shell access or the ability to create files on the local filesystem.

## Affected products

- Exim Exim

## Timeline

- 1997-07-22: disclosed

## References

- [http://www.securityfocus.com/archive/1/7301](http://www.securityfocus.com/archive/1/7301)

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- [Exim Proxy Protocol stack memory disclosure](https://junglewise.ai/threats/cve-2026-94056-exim-before-4-100-1-when-proxy-protocol-is-used-with-an-attacker)
- [Exim before 4.100.1, when certain non-default TLS settings are used with GnuTLS, has a use-after-free.](https://junglewise.ai/threats/cve-2026-94055-exim-before-4-100-1-when-certain-non-default-tls-settings-are)
- [Exim out-of-bounds write in Proxy Protocol v1](https://junglewise.ai/threats/cve-2026-94054-exim-before-4-100-1-when-proxy-protocol-is-used-with-an-attacker)
- [Exim privilege escalation in .forward pipe transport force_command](https://junglewise.ai/threats/cve-2026-66141-exim-privilege-escalation-in-forward-pipe-transport-force-command)