8.1High

CVE-2026-90929

File Browser versions >= 2.5.0 and <= 2.63.23 contain an incorrect authorization flaw in the direct-upload endpoint (resourcePostHandler in http/resource.go). Unlike the TUS upload handler, the direct-upload handler does not reject a target that is an existing directory; a POST with ?override=true aimed at a directory fails inside writeFile (a directory cannot be opened for writing) and the failure-cleanup path then calls Fs.RemoveAll on the request path, recursively deleting the entire tree. This cleanup is gated by neither the Perm.Delete permission nor the checkDescendants rule walk applied by the delete and patch handlers, so an authenticated non-administrator holding only the default Create and Modify permissions can delete directories they are not authorized to delete, including rule-denied files within them. Deletion remains confined to the user's scope because ScopedFs.RemoveAll still enforces the scope guard. The faulty cleanup was introduced in v2.5.0; no patched version is available.

What this means for your business

  • An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 22% of all known flaws.

What to do

  1. 1Ask your IT team or provider whether any of your systems use the affected product.
  2. 2If you do, follow the vendor's guidance. No patch reference has been published yet.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Scoring

CVSS
8.1 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CVSS v4
7.2
Weakness
CWE-863
Assigned by
disclosure@vulncheck.com

Dates

Published
2026-09-14
Last modified
2026-09-14
Sources
NVD

References