Is CVE-2026-54089 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-54089 being exploited in the wild.

How severe is CVE-2026-54089?

Critical severity, with a CVSS score of 9.1, published 25 June 2026.

Which products and versions are affected?

File Browser >= 2.0.0-rc.1, >= 2.0.0-rc.1, = 2.0.0-rc.1, <= 2.63.18, SEMVER:introduced=2.0.0-rc.1, SEMVER:introduced=2.0.0-rc.1,last_affected=2.63.18.

Is there a fix for CVE-2026-54089?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-54089 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-54089?

Check whether you run File Browser, github.com/filebrowser/filebrowser (Go) or github.com/filebrowser/filebrowser/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-54089: File Browser authentication bypass via forged proxy headers

Q: Is there a fix for CVE-2026-54089?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2026-54089 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-54089?

Check whether you run File Browser, github.com/filebrowser/filebrowser (Go) or github.com/filebrowser/filebrowser/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-54089 · Severity: critical · CVSS 9.1 · Published 2026-06-25

File Browser is a web-based file management utility. When configured to use a reverse proxy for authentication, it fails to verify the source of identity headers, allowing any network-based attacker to impersonate any user, including administrators. This can lead to a total compromise of the file server, unauthorized access to all stored data, and the ability to execute arbitrary commands if shell features are enabled.

Technologies: File Browser, github.com/filebrowser/filebrowser (Go), github.com/filebrowser/filebrowser/v2 (Go). Vendors: File Browser, Go.

Quick answers

Is CVE-2026-54089 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-54089 being exploited in the wild.
How severe is CVE-2026-54089?: Critical severity, with a CVSS score of 9.1, published 25 June 2026.
Which products and versions are affected?: File Browser >= 2.0.0-rc.1, >= 2.0.0-rc.1, <= 2.63.18; github.com/filebrowser/filebrowser (Go) SEMVER:introduced=0; github.com/filebrowser/filebrowser/v2 (Go) >= 2.0.0-rc.1, <= 2.63.18, SEMVER:introduced=2.0.0-rc.1, SEMVER:introduced=2.0.0-rc.1,last_affected=2.63.18.
Is there a fix for CVE-2026-54089?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-54089 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-54089?: Check whether you run File Browser, github.com/filebrowser/filebrowser (Go) or github.com/filebrowser/filebrowser/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in the `ProxyAuth.Auth()` function within `auth/proxy.go`. When `auth.method` is set to `proxy`, the application unconditionally trusts the username provided in a configured HTTP header (e.g., `X-Remote-User`) without verifying the request's origin or requiring a shared secret. An attacker can reach the File Browser service directly (bypassing the intended reverse proxy) and provide an arbitrary username to receive a valid JWT. If the provided username does not exist, the application automatically creates a new account with default permissions. This allows for full administrative takeover and unauthorized access to the filesystem.

Affected products

File Browser File Browser >= 2.0.0-rc.1, <= 2.63.18

Identifiers

CVE-2026-54089
GHSA-xqp3-jq6g-x3qm
GO-2026-5966

Timeline

2026-06-03: disclosed: Initial disclosure on GitHub Advisory Database
2026-07-10: advisory: Advisory updated with CVE-2026-54089

References

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