I Just face this issue after upgrade magento version 2.4.2 in security scan "PRODSECBUG-2403 RCE Vulnerability patch has not been detected! (500)".
When I try to find patch PRODSECBUG-2403 not getting this patch.
I found that this issue is fixed in "Magento 2.3.2-p1, Magento 2.3.3"
https://magento.com/security/patches/magento-2.3.3-and-2.2.10-security-update
if this issue already fixed in previous version, Please anyone help me to fix this issue for magento 2.4.2
We have the same problem for the past two weeks. We were not getting that error before that time and we had upgrade to 2.4.2 long before.