What’s Vulnerable › Vulnerabilities
CVE-2023-26490: mailcow is vulnerable to shell command injection via xoauth2 authentication in imapsync
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.2% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2023-03-04 · updated 2026-06-17
- Weakness: CWE-78
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.
Affected products
- mailcow-dockerized: before 2023-03 — fixed in 2023-03
How to fix
Upgrade to a fixed version: mailcow-dockerized 2023-03. Check the vendor advisory for mitigations.
References
- https://github.com/mailcow/mailcow-dockerized/releases/tag/2023-03
- https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-3j2f-wf52-cjg7
- https://github.com/mailcow/mailcow-dockerized/releases/tag/2023-03
- https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-3j2f-wf52-cjg7
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