CVE-2026-77368: high-severity vulnerability in seaweedfs
SeaweedFS: Authenticated Cross-Prefix IDOR in Filer TUS Handler Enables Arbitrary Write to Tenant-Forbidden Paths
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.6epss 0.4%
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L
Affected products
seaweedfs · seaweedfsRelated CVEs — seaweedfs
In the same product, most dangerous first.
CVE-2026-54917HIGHSeaweedFS: Path traversal in the S3 and Iceberg REST gateways allows cross-bucket accessEPSS 1.6%CVE-2026-58372HIGHSeaweedFS < 4.34 - Cross-Bucket Object Deletion via DeleteObjects Request-Body KeysEPSS 0.9%CVE-2026-72920CRITICALSeaweedFS: Unauthenticated filer IAM gRPC service grants S3 administrative controlEPSS 0.8%CVE-2026-55874HIGHSeaweedFS: Path traversal in the S3 gateway X-Amz-Copy-Source header allows cross-bucket object readEPSS 0.6%CVE-2026-73080CRITICALSeaweedFS: Unauthenticated SSRF with response read-back via VolumeServer.FetchAndWriteNeedleEPSS 0.5%CVE-2026-72921HIGHSeaweedFS: Filer JWT allowed_prefixes literal prefix match allows cross-tenant access to sibling pathsEPSS 0.4%