Link following in FileBrowser - #VU139766
Published: July 27, 2026
Vulnerability identifier: #VU139766
CSH Severity: Medium
CVSS v4: 6.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-59
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to delete arbitrary files outside the intended scope and cause a denial of service.
The vulnerability exists due to improper link resolution before file access in the TUS upload-cache eviction logic when expiring in-progress uploads from the default in-memory cache. A remote user can start a TUS upload and swap an ancestor directory for a symlink before cache expiry to delete arbitrary files outside the intended scope and cause a denial of service.
The issue affects only the default in-memory upload cache and requires an out-of-band symlink swap during the cache TTL window.
Affected software
FileBrowser
Remediation
Install security update from vendor's website.
FileBrowser - update to 2.63.19