# CVE-2026-72836

## Summary

- **CVE ID:** CVE-2026-72836
- **Severity:** CRITICAL
- **CVSS Score:** 9.2 (CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-178
- **Published:** Aug 14, 2026
- **Last Modified:** Aug 18, 2026

## 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 — filebrowser (0)
- filebrowser — filebrowser (2.63.19)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.41%
- **EPSS Percentile:** 34.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._