CVE-2021-44548

CVE-2021-44548 is an improper input validation vulnerability in Apache Solr's DataImportHandler, specifically affecting Windows installations of Solr versions prior to 8.11.1. An unauthenticated attacker can exploit this by providing a Windows UNC path, forcing the Solr host to initiate an SMB network call. This critical vulnerability (CVSS 9.8) can lead to sensitive data exfiltration (e.g., NTLM hashes) or, in misconfigured systems, SMB Relay Attacks resulting in user impersonation or remote code execution. While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community discussion, indicating awareness and potential for future exploitation.