Use of a Broken or Risky Cryptographic Algorithm
Elasticsearch x-pack-security plugin before 7.8.1 contain a username disclosure flaw was found in the API Key service. An unauthenticated attacker could send a specially crafted request and determine if a username exists in the Elasticsearch native realm.
CWE-327 - Use of a Broken or Risky Cryptographic Algorithm
The use of a broken or risky cryptographic algorithm is an unnecessary risk that may result in the exposure of sensitive information.