Description
aiosmptd is a reimplementation of the Python stdlib smtpd.py based on asyncio. Prior to version 1.4.6, servers based on aiosmtpd accept extra unencrypted commands after STARTTLS, treating them as if they came from inside the encrypted connection. This could be exploited by a man-in-the-middle attack. Version 1.4.6 contains a patch for the issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| aio-libs | aiosmtpd | < 1.4.6 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-aiosmtpd | 1.4.6-1 | — |
| Debian 13 | python-aiosmtpd | 1.4.6-1 | — |
| Debian 12 | python-aiosmtpd | 1.4.3-1.1+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | python-aiosmtpd | No fix yet | — |
| Ubuntu 26.04 LTS | python-aiosmtpd | No fix yet | — |
| Ubuntu 25.10 | python-aiosmtpd | No fix yet | — |
| Ubuntu 24.04 LTS | python-aiosmtpd | No fix yet | — |
| Ubuntu 22.04 LTS | python-aiosmtpd | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | python-aiosmtpd | No fix yet | — |
| Ubuntu 18.04 LTS | python-aiosmtpd | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP5 | python-aiosmtpd | 1.2.1-bp155.3.3.1 | openSUSE-SU-2024:0243-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-aiosmtpd | 1.4.6-6.1 | openSUSE-SU-2026:11675-1 |
| openSUSE Leap 15.5 | python-aiosmtpd | 1.2.1-bp155.3.3.1 | openSUSE-SU-2024:0243-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | aiosmtpd | < 1.4.6 | 1.4.6 | GHSA-wgjv-9j3q-jhg8 |
Advisories 2
- openSUSE-SU-2026:11675-1 python313-aiosmtpd-1.4.6-6.1 on GA media SUSE / openSUSE Security Updates · Sep 3, 2026
- openSUSE-SU-2024:0243-1 Security update for python-aiosmtpd SUSE / openSUSE Security Updates · Feb 4, 2026