CVE-2021-32040: 
MongoDB vulnerability analysis and mitigation

MongoDB versions prior to 5.0.4, 4.4.11, and 4.2.16 contain a vulnerability related to extremely long aggregation pipelines that could lead to a Denial of Service (DoS) condition. The vulnerability, tracked as CVE-2021-32040, was discovered and later patched in MongoDB's security updates (NVD, NetApp Advisory).

The vulnerability has a CVSS 3.0 score of 8.1, indicating a high severity level. The vulnerability is related to the handling of aggregation pipelines in MongoDB, specifically affecting the $unionWith, $match, and $group stages. If an attacker could cause such an aggregation to occur, they could potentially crash MongoDB (ManageEngine).

Successful exploitation of this vulnerability could lead to a Denial of Service (DoS) condition, potentially causing MongoDB instances to crash. The vulnerability has a network attack vector with low attack complexity and requires no privileges or user interaction to exploit (NetApp Advisory).

The vulnerability has been fixed in MongoDB versions 5.0.4, 4.4.11, and 4.2.16. Users are advised to upgrade to these or later versions to mitigate the vulnerability. No specific workarounds have been provided for systems that cannot be immediately updated (NetApp Advisory).