A vulnerability was found in Netentsec NS-ASG Application Security Gateway 6.3. It has been classified as critical. Affected is an unknown function of the file /admin/list_localuser.php. The manipulation of the argument ResId leads to sql injection. Using CWE to declare the problem leads to CWE-89. The weakness was published 02/29/2024. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2024-2021. It is possible to launch the attack remotely. Technical details are available. Furthermore, there is an exploit available. The exploit has been disclosed to the public and may be used. The current price for an exploit might be approx. USD $0-$5k at the moment. The MITRE ATT&CK project declares the attack technique as T1505. It is declared as proof-of-concept. The exploit is shared for download at github.com. As 0-day the estimated underground price was around $0-$5k. The vendor was contacted early about this disclosure but did not respond in any way. A possible mitigation has been published before and not just after the disclosure of the vulnerability.