In Elasticsearch versions before 7.13.3 and 6.8.17 an uncontrolled recursion vulnerability that could lead to a denial of service attack was identified in the Elasticsearch Grok parser. A user with the ability to submit arbitrary queries to Elasticsearch could create a malicious Grok query that will crash the Elasticsearch node.
{
"cpes": [
"cpe:2.3:a:elastic:elasticsearch:*:*:*:*:*:*:*:*"
],
"severity": "Medium"
}