Critical 9.1Published Jun 25, 2026

CVE-2026-54089File Browser: Authentication Bypass via Proxy Auth Header Forgery

Updated under an hour ago (Oct 26, 2026, 8:40 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 9.1 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-287, CWE-290
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jun 25, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

filebrowser filebrowser filebrowser:filebrowser (from the name)	from 2.0.0-rc.1	CNA record

References

https://github.com/filebrowser/filebrowser/security/advisories/GHSA-xqp3-jq6g-x3qmx-refsource-confirm
https://github.com/filebrowser/filebrowser/blob/main/auth/proxy.gox-refsource-misc
https://github.com/filebrowser/filebrowser/blob/main/http/auth.go#L121-L137x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.