ImpressCMS <= 1.4.3 (findusers.php) SQL Injection Vulnerability

• Affected Versions:

Version 1.4.3 and prior versions.

• Vulnerability Description:

The vulnerability is located in the /include/findusers.php script:

281$total = $user_handler->getUserCountByGroupLink(@$_POST["groups"], $criteria);
283$validsort = array("uname", "email", "last_login", "user_regdate", "posts");
284$sort = (!in_array($_POST['user_sort'], $validsort)) ? "uname" : $_POST['user_sort'];
285$order = "ASC";
286if (isset($_POST['user_order']) && $_POST['user_order'] == "DESC") {
287    $order = "DESC";
294$foundusers = $user_handler->getUsersByGroupLink(@$_POST["groups"], $criteria, TRUE);

User input passed through the “groups” POST parameter is not properly sanitized before being used in a call to the icms_member_Handler::getUserCountByGroupLink() and icms_member_Handler::getUsersByGroupLink() methods at lines 281 and 294. These methods use the first argument to construct a SQL query without proper validation, and this can be exploited by remote attackers to e.g. read sensitive data from the “users” database table through boolean-based SQL Injection attacks. The application allows for stacked SQL queries, as such this vulnerability could be exploited to e.g. create a new admin user and execute arbitrary PHP code.

• Solution:

Upgrade to version 1.4.4 or later.

• Disclosure Timeline:

[19/01/2021] – Vendor notified through HackerOne

[29/01/2021] – Vulnerability acknowledged by the vendor

[03/02/2021] – CVE number assigned

[06/02/2022] – Version 1.4.3 released, vulnerability not correctly fixed

[11/02/2022] – Vendor was informed about the ineffective fix

[09/03/2022] – Version 1.4.4 released

[22/03/2022] – Public disclosure

• CVE Reference:

The Common Vulnerabilities and Exposures project ( has assigned the name CVE-2021-26599 to this vulnerability.

• Credits:

Vulnerability discovered by Egidio Romano.

• Other References: