SeaweedFS up to 4.23 Authorization Check filer_server_handlers.go strings.HasPrefix improper authorization

Summaryinfo

A vulnerability classified as very critical was found in SeaweedFS up to 4.23. This issue affects the function strings.HasPrefix of the file weed/server/filer_server_handlers.go of the component Authorization Check. Executing a manipulation can lead to improper authorization. This vulnerability is registered as CVE-2026-72921. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in SeaweedFS up to 4.23. It has been declared as very critical. This vulnerability affects the function strings.HasPrefix of the file weed/server/filer_server_handlers.go of the component Authorization Check. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

SeaweedFS is a distributed storage system. Prior to 4.24, the weed/server/filer_server_handlers.go allowed_prefixes authorization check used strings.HasPrefix on raw path strings, so a filer JWT scoped to /tenant1 also authorized sibling paths such as /tenant1234, /tenant1-old, and /tenant1backup, enabling cross-tenant reads and writes with a valid scoped token. This issue is fixed in version 4.24.

The advisory is available at github.com. This vulnerability was named CVE-2026-72921 since 08/10/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/11/2026). This vulnerability is assigned to T1548.002 by the MITRE ATT&CK project.

Upgrading to version 4.24 eliminates this vulnerability.

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Productinfo

Name

• SeaweedFS

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15
• 4.16
• 4.17
• 4.18
• 4.19
• 4.20
• 4.21
• 4.22
• 4.23

Website

• Product: https://github.com/seaweedfs/seaweedfs/

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