The VictoriaMetrics vmrestore utility does not validate backup part path components before writing restored files to the local filesystem. An attacker who can provide or modify a backup source can craft object names containing .. path components that cause vmrestore to write files outside the intended -storageDataPath restore root, subject to the permissions of the vmrestore process.
Impact
An attacker who can supply or modify the backup source -- for example by writing malicious object names to a compromised or misconfigured storage bucket -- can cause arbitrary files to be created or overwritten on the host running vmrestore, within the limits of the process's filesystem permissions.
VictoriaMetrics' security model assumes backup sources are trusted and access-controlled. This vulnerability requires an attacker to have write access to the backup storage (e.g. S3, GCS, or Azure Blob Storage bucket) used as the -src for vmrestore. Under a correctly secured deployment where backup storage access is properly restricted, unauthorized exploitation of this issue should not be possible. Users are advised to follow the principle of least privilege when granting access to backup storage buckets.