CVE-2026-123620: Command Injection (CVSS 7.5)

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.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0138

Probability of exploitation

0.72%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-78 OS Command Injection

References

Other References

https://github.com/webmin/usermin https://github.com/webmin/usermin/blob/2.570/mailbox/mailbox-lib.pl#L1031-L1040 https://github.com/webmin/usermin/commit/8a45420282ff04c943f05d9241a3c55afb9bca79 https://github.com/webmin/usermin/issues/142 https://hackmd.io/@leediay/H144QKY6zl https://www.vulncheck.com/advisories/usermin-through-2.570-os-command-injection-via-read-mail-imap-folder-deletion

Frequently Asked Questions

What is CVE-2026-123620? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-123620? +

CVE-2026-123620 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0138, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-123620? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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