# CVE-2026-50891: Filestash incorrect access control in /admin/api/config

Source: https://junglewise.ai/threats/cve-2026-50891-filestash-incorrect-access-control-in-admin-api-config  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-15. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-50891 · Severity: high · CVSS 8.1 · Published 2026-06-15

Filestash is a file management system accessible via web interface. An attacker can take over the administrative console of a freshly deployed Filestash instance before setup is completed by sending a crafted request to modify the admin password. This grants complete control over file storage, sharing permissions, and configuration settings.

Technologies: [github.com/mickael-kerjean/filestash (Go)](https://junglewise.ai/threats/technologies/github-com-mickael-kerjean-filestash). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-50891 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-50891 being exploited in the wild.

**How severe is CVE-2026-50891?** High severity, with a CVSS score of 8.1, published 15 June 2026.

**Which products and versions are affected?** Filestash 0.4.0; github.com/mickael-kerjean/filestash (Go) <= 0.2.2-0.20260827111952-cbcd1e96ebc7, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=0.2.2-0.20260827111952-cbcd1e96ebc7.

**Is there a fix for CVE-2026-50891?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-50891 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-50891?** Check whether you run Filestash or github.com/mickael-kerjean/filestash (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an improper access control issue (CWE-284) in the AdminOnly middleware of Filestash. The middleware only enforces admin authentication checks when auth.admin is non-empty; during initial setup, this field is unset, allowing unauthenticated access to /admin/api/config. An attacker can issue GET /admin/api/config to retrieve the current configuration, modify the auth.admin password hash field with a bcrypt hash of their chosen password, and POST the modified JSON to persist the change. No authentication, user interaction, or elevated privileges are required; the only precondition is network reachability to the uninitialized instance. Successful exploitation results in complete administrative takeover of the application, including access to global configuration, storage definitions, secrets, and sharing behavior. As of the advisory publication, no patched version is available.

## Affected products

- Mickael Kerjean Filestash <= 0.2.2-0.20260827111952-cbcd1e96ebc7

## Identifiers

- CVE-2026-50891
- GHSA-rcqf-cpv9-g5jf
- GO-2026-6300

## Timeline

- 2026-06-15: disclosed: Advisory published to GitHub
- 2026-08-27: advisory: GitHub reviewed and updated advisory

## References

- [https://gist.github.com/pyuysig/50dc365f54f95396bb67532f02b34bb0](https://gist.github.com/pyuysig/50dc365f54f95396bb67532f02b34bb0)

## Related threats

- [Filestash configured to skip TLS certificate verification when using the FTPS protocol](https://junglewise.ai/threats/cve-2024-41255-filestash-configured-to-skip-tls-certificate-verification-when)
- [Filestash skips TLS certificate verification process when sending out email verification codes](https://junglewise.ai/threats/cve-2024-41256-filestash-skips-tls-certificate-verification-process-when-sending)