CVE-2023-26490: mailcow is a dockerized email package, with multiple containers linked in one bridged network. The Sync Job feature - which can be made available to s...

Description

mailcow is a dockerized email package, with multiple containers linked in one bridged network. The Sync Job feature - which can be made available to standard users by assigning them the necessary permission - suffers from a shell command injection. A malicious user can abuse this vulnerability to obtain shell access to the Docker container running dovecot. The imapsync Perl script implements all the necessary functionality for this feature, including the XOAUTH2 authentication mechanism. This code path creates a shell command to call openssl. However, since different parts of the specified user password are included without any validation, one can simply execute additional shell commands. Notably, the default ACL for a newly-created mailcow account does not include the necessary permission. The Issue has been fixed within the 2023-03 Update (March 3rd 2023). As a temporary workaround the Syncjob ACL can be removed from all mailbox users, preventing from creating or changing existing Syncjobs.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.22%

80.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-78

Affected Software

Vendor	Product	Versions
Mailcow	Mailcow\	< 2023-03

References

https://github.com/mailcow/mailcow-dockerized/releases/tag/2023-03Release Notes
https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-3j2f-wf52-cjg7Exploit, Third Party Advisory
https://github.com/mailcow/mailcow-dockerized/releases/tag/2023-03Release Notes
https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-3j2f-wf52-cjg7Exploit, Third Party Advisory

Timeline

Published: Mar 4, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-26490?

mailcow is a dockerized email package, with multiple containers linked in one bridged network. The Sync Job feature - which can be made available to standard users by assigning them the necessary permission - suffers from a shell command injection. A malicious user can abuse this vulnerability to obtain shell access to the Docker container running dovecot. The imapsync Perl script implements all the necessary functionality for this feature, including the XOAUTH2 authentication mechanism. This code path creates a shell command to call openssl. However, since different parts of the specified user password are included without any validation, one can simply execute additional shell commands. Notably, the default ACL for a newly-created mailcow account does not include the necessary permission. The Issue has been fixed within the 2023-03 Update (March 3rd 2023). As a temporary workaround the Syncjob ACL can be removed from all mailbox users, preventing from creating or changing existing Syncjobs.

How severe is CVE-2023-26490?

CVE-2023-26490 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 2.22% probability of exploitation in the next 30 days.

How do I fix CVE-2023-26490?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.