The vulnerability exists in the AWS ParallelCluster CLI export-cluster-logs and export-image-logs commands before version 3.16.0. An attacker who can authenticate to AWS and has write permissions to the S3 bucket used for log export can craft a malicious S3 object key that causes the CLI to write files outside the intended export directory on the machine executing the command. These files are created with names and contents controlled by the attacker and inherit the privileges of the CLI process, allowing potential persistence or further local exploitation.

AWS ParallelCluster CLI versions older than 3.16.0 are vulnerable. The issue appears when the export commands are run against an S3 bucket with write access; all machines that have those CLI versions and possess the required IAM permissions are affected.

The CVSS score of 5.9 indicates moderate severity. No EPSS data is available, but the flaw requires an authenticated user with specific S3 write privileges and the use of the CLI on the target machine. The vulnerability is not listed in the CISA KEV catalog. When exploited, it allows arbitrary file creation on the local filesystem, which could be leveraged for further local attacks or persistence. The attack vector is inferred to be local to the machine running the CLI, with the prerequisite of remote AWS authentication and bucket write access.