What’s Vulnerable › Vulnerabilities

CVE-2026-72836: FileBrowser before 2.63.19 Case Sensitivity Authentication Bypass

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-14 · updated 2026-09-08
• Weakness: CWE-178

Description

FileBrowser before 2.63.19 does not account for case-insensitive filesystems when checking home directory ownership during self-registration. When Signup and CreateUserDir are enabled and FileBrowser's root is on a case-insensitive filesystem (confirmed on Windows/NTFS), two self-registered usernames that differ only in letter case (e.g., CaseVictim and casevictim) are stored as distinct accounts but resolve to the same physical home directory, because the scope-ownership check compares the persisted scope as an exact case-sensitive string. A second registrant can therefore read, overwrite, and delete another account's files through authenticated HTTP endpoints, without needing an existing account or victim interaction.

Affected products

• filebrowser: before 2.63.19 — fixed in 2.63.19

How to fix

Upgrade to a fixed version: filebrowser 2.63.19. Check the vendor advisory for mitigations.

References

• https://github.com/filebrowser/filebrowser/commit/fe7efb2e6afe66774cd86a5b0a03033bd514d0c0
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-576v-w77m-gr84
• https://www.vulncheck.com/advisories/filebrowser-before-case-sensitivity-authentication-bypass
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-576v-w77m-gr84

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