TI-2026-39018 Aliases CVE-2026-54089 GHSA-xqp3-jq6g-x3qm

File Browser: Authentication Bypass via Proxy Auth Header Forgery

HIGH 80CWE-287Published 2026-06-25 · Updated 2026-06-25

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · None
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

Summary

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Starting with 2.0.0-rc.1, when FileBrowser is configured with proxy authentication (auth.method=proxy), any unauthenticated attacker who can reach the server directly can impersonate any user - including admin - by sending a single forged HTTP header. No credentials are required. Additionally, specifying a non-existent username causes the server to automatically create a new user account, providing an account creation primitive with no authorization. This is an already known issue that has been documented in the documentation for several years, but has not been documented as a vulnerability before.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00612 49th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
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	>= 2.0.0-rc.1	—	No fix listed	CNA
—	github.com/filebrowser/filebrowser/v2 (Go)	2.0.0-rc.1 – 2.63.18	—	No fix listed	GHSA-xqp3-jq6g-x3qm

filebrowser Vendorfilebrowser Affected >= 2.0.0-rc.1 Fixed in — No fix listed CNA
github.com/filebrowser/filebrowser/v2 (Go) Vendor— Affected 2.0.0-rc.1 – 2.63.18 Fixed in — No fix listed GHSA-xqp3-jq6g-x3qm

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-2026-54089
2026-10-03 Alias added: GHSA-xqp3-jq6g-x3qm

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-54089

Other 4

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-2026-39017 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
TI-2025-33000 File Browser vulnerable to command execution allowlist bypass CVSS 3.1HIGH 8.1

See all 64 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences