# CVE-2026-77317: SeaweedFS SFTP path ACL literal prefix matching bypass

Source: https://junglewise.ai/threats/cve-2026-77317-seaweedfs-sftp-path-acl-literal-prefix-matching-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-26. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-77317 · Severity: high · CVSS 8.1 · Published 2026-08-26

SeaweedFS is a distributed storage system offering SFTP access to files and blobs. An authenticated SFTP user with limited permissions to a specific path (e.g., /tenants/alice) can also access sibling paths that share the same name prefix (e.g., /tenants/alice-archive or /tenants/alice2), bypassing the intended access controls and potentially exposing or modifying other tenants' data.

Technologies: [SeaweedFS](https://junglewise.ai/threats/technologies/seaweedfs). Vendors: [SeaweedFS](https://junglewise.ai/threats/vendors/seaweedfs).

## Quick answers

**Is CVE-2026-77317 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77317 being exploited in the wild.

**How severe is CVE-2026-77317?** High severity, with a CVSS score of 8.1, published 26 August 2026.

**Which products and versions are affected?** SeaweedFS 3.88 through 4.39.

**Is there a fix for CVE-2026-77317?** A patch was published on 2026-07-10: Fix committed; released in version 4.40 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-77317 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-77317?** Check whether you run SeaweedFS 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 SFTP server in SeaweedFS uses strings.HasPrefix() for path ACL validation instead of enforcing path-component boundaries. A user granted access to /tenants/alice matches any path starting with that string, including siblings like /tenants/alice-archive, /tenants/alice-backup, or /tenants/alice2. The vulnerability affects SFTP users with a root home directory (HomeDir: "/") and scoped permissions; an authenticated attacker can read or overwrite files in unintended sibling paths if granted read or write permissions. The fix, released in version 4.40, uses path normalization and requires either exact path equality or separator-delimited descendant validation via a pathWithin() helper function.

## Affected products

- SeaweedFS SeaweedFS 3.88 through 4.39

## Timeline

- 2026-08-26: disclosed
- 2026-07-10: patched: Fix committed; released in version 4.40

## References

- [https://github.com/seaweedfs/seaweedfs/commit/29981f8d24a62e9571962c4534fb23c48c00bae2](https://github.com/seaweedfs/seaweedfs/commit/29981f8d24a62e9571962c4534fb23c48c00bae2)
- [https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-fvpg-g364-j8vh](https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-fvpg-g364-j8vh)

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