What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-25 · updated 2026-06-25
• Weakness: CWE-287

Description

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.

Affected products

• filebrowser: from 2.0.0-rc.1

References

• https://github.com/filebrowser/filebrowser/blob/main/auth/proxy.go
• https://github.com/filebrowser/filebrowser/blob/main/http/auth.go#L121-L137
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-xqp3-jq6g-x3qm
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-xqp3-jq6g-x3qm

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