SeaweedFS: Authenticated Cross-Prefix IDOR in Filer TUS Handler Enables Arbitrary Write to Tenant-Forbidden Paths

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-77368
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-26 22:16:29 UTC
Updated2026-08-26 22:16:29 UTC
DescriptionSeaweedFS 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.

Risk And Classification

Primary CVSS: v3.1 7.6 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

Problem Types: CWE-639 | CWE-639 CWE-639: Authorization Bypass Through User-Controlled Key

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.6HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L
3.1CNADECLARED7.6HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Seaweedfs Seaweedfs affected >= 4.39, < 4.40 Not specified

References

ReferenceSourceLinkTags
github.com/seaweedfs/seaweedfs/commit/fa549e9c83b7799d512157d728f5205291... [email protected] github.com
github.com/seaweedfs/seaweedfs/security/advisories/GHSA-99q7-x53r-6j4g [email protected] github.com
github.com/seaweedfs/seaweedfs/commit/ce82e3a057080162a9fba11889157d2255... [email protected] github.com
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