CVE-2026-123620 is a high-severity (CVSS 7.5) OS Command Injection vulnerability in webmin usermin. Versions up to 2.570 are affected; the records list no fixed version yet, so check the vendor advisory below.
Usermin through 2.570 contains an OS command injection vulnerability in the Read Mail module that allows authenticated users to execute commands through unsanitized IMAP folder names.…
Description
Usermin through 2.570 contains an OS command injection vulnerability in the Read Mail module that allows authenticated users to execute commands through unsanitized IMAP folder names. Attackers can create a folder containing shell metacharacters via an external IMAP client, then delete it in Usermin to run commands as their system account, bypassing webmail-only restrictions.
Affected Products
userminwebminDetection & mitigation playbook
Vendor / applianceDetect
Inventory every webmin usermin deployment and check each version against the affected-products list above.
Remediation status
The records we use list no fixed version for CVE-2026-123620 (versions up to 2.570 are affected). Check the webmin usermin advisory for a patched release, and apply the workarounds below until you can upgrade.
Mitigate without a patch
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2026-123620 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.