# CVE-2020-8794: opensmtpd: OpenSMTPD before 6.6.4 allows remote code execution because of anout-of-bounds read in mta_io in mta_session.c for mu...

CVE-2020-8794 is fixed in opensmtpd on 1 platform, first by opensmtpd 6.0.3p1-1ubuntu0.2, released February 25, 2020. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2020-8794
- Priority: High
- CVSS: n/a (High)
- EPSS: 0.8890
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 25, 2020

## Description

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

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | opensmtpd Ubuntu 18.04.6 LTS (bionic) | 6.0.3p1-1ubuntu0.2 | [opensmtpd 6.0.3p1-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-opensmtpd-6.0.3p1-1ubuntu0.2.md) | Feb 25, 2020 |
| Linux | opensmtpd Ubuntu 20.04 LTS (focal) | 6.6.4p1-1 | [opensmtpd 6.6.4p1-1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-opensmtpd-6.6.4p1-1.md) | Feb 25, 2020 |
| Linux | opensmtpd Ubuntu 24.10 (oracular) | 6.6.4p1-1 | [opensmtpd 6.6.4p1-1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-opensmtpd-6.6.4p1-1.md) | Jan 16, 2026 |
| Linux | opensmtpd Ubuntu 25.04 (plucky) | 6.6.4p1-1 | [opensmtpd 6.6.4p1-1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-opensmtpd-6.6.4p1-1.md) | Jan 16, 2026 |

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