CVE-2026-84320: Nginx UI: Auto backup name allows path traversal outside validated storage path
Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.3, Nginx UI validates an automatic backup's storagepath, but AutoBackup.GetName returns a user-controlled name without rejecting path separators or parent-directory components, and downstream filename formatting embeds that result in the final archive filename. An authenticated user who can create or modify an automatic backup can cause filepath.Join to resolve the generated archive path outside the validated storage directory, allowing backup archives to be written with the Nginx UI process privileges. For encrypted configuration backups, the adjacent encryption key file can also be written outside the validated directory. This issue is fixed in version 2.4.3.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Nginx UIto a version that resolves this vulnerability.Fixed in 2.4.3
Event History
Frequently Asked Questions
Who can exploit this issue?
An authenticated user who has permission to create or modify an automatic backup can exploit it. No user interaction is required.
What can an attacker do with a successful exploit?
They can cause backup archives to be written outside the validated backup storage directory, using the privileges of the Nginx UI process. When encrypted configuration backups are used, the associated encryption key file can also be written outside that directory.
Which versions need remediation?
Nginx UI versions prior to 2.4.3 are affected. The issue is fixed in version 2.4.3.
How can administrators reduce exposure before upgrading?
Restrict the ability to create or modify automatic backups to trusted authenticated users. The vulnerable path is reached through user-controlled automatic backup names.