# CVE-2026-72839: filebrowser through 2.63.16 Privilege Escalation via Signup

> Unauthenticated attackers can register accounts with full root scope permissions when self-signup is enabled, leading to unrestricted file access and modification.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/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:** 13 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-6759-996p-gpj6, GHSA-6g9f-8x2v-mq2c

## What is CVE-2026-72839?

CVE-2026-72839 is a critical vulnerability in filebrowser, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

filebrowser through 2.63.16 fails to properly restrict scope and permissions when self-signup is enabled with default CreateUserDir setting. Unauthenticated attackers can register accounts that inherit the server root scope with full create, modify, delete, rename, share, and download permissions, allowing unrestricted access to all files.

Weakness: CWE-266 (Incorrect Privilege Assignment)

## Which versions are affected by CVE-2026-72839?


## How do I fix CVE-2026-72839?

No fix has been published for CVE-2026-72839 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-72839 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72839 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72839 and fix it if it is affected.

What it is: CVE-2026-72839 is a critical vulnerability in filebrowser, published on 13 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-2026-72839 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-2026-72839/ (Markdown: https://insights.sbomify.com/CVE-2026-72839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72839
- OSV: https://osv.dev/vulnerability/CVE-2026-72839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72839/
Summaries are generated and may contain mistakes; the official description above is the record.