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

> Attackers can bypass home directory ownership checks on case-insensitive filesystems to read, modify, or delete other users' files.

- **Severity:** Critical 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** GHSA-576v-w77m-gr84, GHSA-f37p-wpgx-m9mr

## What is CVE-2026-72836?

CVE-2026-72836 is a critical authentication bypass vulnerability in filebrowser, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-178 (Improper Handling of Case Sensitivity)

## Which versions are affected by CVE-2026-72836?


## How do I fix CVE-2026-72836?

No fix has been published for CVE-2026-72836 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-72836 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72836 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72836 and fix it if it is affected.

What it is: CVE-2026-72836 is a critical authentication bypass vulnerability in filebrowser, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72836 exists.

Affected product: filebrowser. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-72836/ (Markdown: https://insights.sbomify.com/CVE-2026-72836/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72836
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72836
- OSV: https://osv.dev/vulnerability/CVE-2026-72836

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72836/
Summaries are generated and may contain mistakes; the official description above is the record.