It was discovered that on Windows operating systems specifically, Kibana was not validating a user supplied path, which would load .pbf files. Because of this, a malicious user could arbitrarily traverse the Kibana host to load internal files ending in the .pbf extension. Thanks to Dominic Couture for finding this vulnerability.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-37938
• https://discuss.elastic.co/t/kibana-7-15-2-security-update/288923