EUVD-2026-39508
GHSA-xqp3-jq6g-x3qm
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Once proxy auth is enabled, a single forged header gives unauthenticated remote admin (AV:N/AC:L/PR:N/UI:N); full file read/write/delete justifies C:H/I:H/A:H, with the non-default config noted as a deployment precondition rather than attacker complexity.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
1DescriptionCVE.org
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.
AnalysisAI
Authentication bypass and privilege escalation in File Browser (versions 2.0.0-rc.1 and later) lets a remote unauthenticated attacker impersonate any account - including admin - by sending a single forged HTTP header when the server runs with proxy authentication (auth.method=proxy). The same flaw doubles as an unauthorized account-creation primitive, since supplying a non-existent username silently provisions a new user. Scored CVSS 9.1 (CWE-287); no public exploit identified at time of analysis, though the underlying behavior has been openly documented for years.
Technical ContextAI
File Browser is a Go-based self-hosted web interface for browsing, uploading, editing, and deleting files in a target directory, identified here by cpe:2.3:a:filebrowser:filebrowser. The issue lives in its proxy-authentication mode (auth/proxy.go and http/auth.go around lines 121-137), a deployment pattern intended for use behind a trusted reverse proxy that performs authentication and injects the verified identity into a request header. The root cause is CWE-287 (Improper Authentication): the application trusts the user-identity header unconditionally and does not verify that the request actually originated from the trusted proxy. When the server is reachable directly (bypassing the proxy), an attacker controls that header outright, so identity assertion collapses into a client-supplied value.
RemediationAI
No vendor-released patch version was identified at time of analysis; the GitHub advisory (https://github.com/filebrowser/filebrowser/security/advisories/GHSA-xqp3-jq6g-x3qm) documents the issue, so monitor it for a fixed release and upgrade once published. As immediate compensating controls: if you do not require proxy authentication, switch auth.method away from proxy (e.g., to JSON/password or noauth-behind-proxy as appropriate) to eliminate the trusted-header assumption entirely. If proxy auth is required, ensure the File Browser process is never directly reachable - bind it to localhost or an internal interface and force all traffic through the reverse proxy (trade-off: requires correct network segmentation and breaks any direct-access workflows), and configure the proxy to strip and re-set the identity header on every inbound request so client-supplied values cannot pass through (trade-off: misconfiguration silently reopens the bypass). Additionally restrict network access to the service port via firewall rules to the proxy host only, and audit user accounts for unexpected auto-created usernames.
More in Filebrowser
View allUnauthorized file operations in File Browser before fix. PoC and patch available.
A cross-site scripting (XSS) vulnerability in FileBrowser before v2.23.0 allows an authenticated attacker to escalate pr
Recursive operation authorization bypass in File Browser before v2.63.22 permits any authenticated user to copy, rename,
Path normalization bypass in Filebrowser prior to 2.57.1 allows authenticated users to circumvent file access restrictio
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ
File Browser versions 2.50.0 through 2.63.21 permit indefinite session persistence via expired JWT tokens when proxy aut
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ
Arbitrary file deletion in filebrowser before 2.63.19 allows authenticated users holding only Create permission to delet
File Browser versions prior to 2.61.0 incorrectly set the filesystem root to a parent directory when generating public s
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ
Same weakness CWE-287 – Improper Authentication
View allSame technique Authentication Bypass
View allVendor StatusVendor
SUSE
Severity: Critical| Product | Status |
|---|---|
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
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External POC / Exploit Code
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