CVE-2023-26490
Command Injection in Mailcow\ _dockerized
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-26490 is a high-severity OS Command Injection (CWE-78) vulnerability in Mailcow Mailcow\. Its CVSS base score is 7.3 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique NTDS (T1003.003); ranked in the top 18% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
mailcow is a dockerized email package that links multiple containers in a single bridged network. The Sync Job feature, which can be enabled for standard users via an ACL, contains a command injection vulnerability (CWE-78) in the imapsync Perl script. When constructing a shell command that invokes openssl for XOAUTH2 authentication, portions of the user-supplied password are incorporated without validation, allowing arbitrary command execution inside the dovecot container.
An attacker who obtains the Sync Job permission can exploit the flaw to gain shell access within the affected container. The permission is not granted by default to newly created mailcow accounts, limiting exposure to users who have been explicitly assigned the ACL or to accounts created before the default policy was enforced.
The vulnerability was addressed in the 2023-03 mailcow release published on 3 March 2023. As an interim mitigation, administrators can remove the Syncjob ACL from all mailbox users to prevent creation or modification of sync jobs. The corresponding GitHub Security Advisory and release notes document the fix and the workaround.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-30292
Vulnerability Data
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.…
more
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.5V1.2.8
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.
Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.