CVE-2026-77368: seaweedfs

Vulnerability summary

CVE-2026-77368 is a high (CVSS 7.6) vulnerability in seaweedfs. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.9% of scored vulnerabilities.

Timeline

1. 26-08-2026
   PublishedVulnerability first disclosed.
2. 27-08-2026
   Last modifiedVulnerability information updated.

Description

SeaweedFS is a distributed storage system for files and blobs. In version 4.39, the filer's TUS resumable-upload handler checks JWT allowed_prefixes scoping only when a session is created, letting a low-privilege tenant hijack another tenant's upload session to write content to filer paths their own token forbids. The HEAD, PATCH, and DELETE verbs that act on an existing session by its id never verify that the session's stored target path falls within the caller's allowed prefixes, so a tenant who obtains another upload's session identifier can PATCH attacker bytes into it and, on completion, have the file land at the victim's out-of-scope path. The same token can also DELETE other tenants' sessions and HEAD them to read upload progress and size, defeating the JWT prefix isolation. This vulnerability only affects deployments that configure filer JWT signing and have TUS uploads enabled. This issue is fixed in version 4.40.

• CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.