File Browser 2.5.0 Directory Deletion via Upload Failure Cleanup
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| filebrowser | filebrowser | 2.5.0 – 2.63.23 | — | No fix listed | CNA |
- filebrowser Vendorfilebrowser Affected 2.5.0 – 2.63.23 Fixed in — No fix listed CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:filebrowser:filebrowser:*:*:*:*:*:*:*:* | — | — | filebrowser |
- cpe:2.3:a:filebrowser:filebrowser:*:*:*:*:*:*:*:* Versions — — ·filebrowser
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90929
- 2026-10-03 Alias added: GHSA-78rx-w3p8-c3v7
References
More filebrowser vulnerabilities
- TI-2026-25251 File Browser Self Registration Grants Any User Admin Access When Default Permissions Include Admin CVSS 4.0CRITICAL 10.0
- TI-2026-51065 filebrowser through 2.63.16 Privilege Escalation via Signup CVSS 4.0CRITICAL 9.3
- TI-2026-39018 File Browser: Authentication Bypass via Proxy Auth Header Forgery CVSS 3.1CRITICAL 9.1
- TI-2026-39017 File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE) CVSS 4.0CRITICAL 9.3
- TI-2026-23305 File Browser: TUS Delete Endpoint Bypasses Delete Permission Check CVSS 3.1CRITICAL 9.1
- TI-2026-26777 File Browser's Signup Grants Execution Permissions When Default Permissions Includes Execution CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-90929 · CVE Program
- CVE-2026-90929 · NVD
- FIRST EPSS
- GHSA-78rx-w3p8-c3v7 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences