SeaweedFS up to 4.39 S3 API improper authorization

Summaryinfo

A vulnerability was found in SeaweedFS up to 4.39. It has been declared as critical. Affected is an unknown function of the component S3 API. Executing a manipulation can lead to improper authorization. This vulnerability is registered as CVE-2026-77298. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as critical was found in SeaweedFS up to 4.39. This vulnerability affects some unknown processing of the component S3 API. 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 for files and blobs. In versions 4.39 and earlier, the S3 API accepts an external OIDC JWT sent directly in the Authorization header and maps it to an IAM role without enforcing that role's trust policy, so a federated user can assume a role they are not permitted to hold. The standard STS AssumeRoleWithWebIdentity path rejects such a token when the role's trust policy does not trust the token's federated provider, but the direct S3 bearer path validates only the token itself and then authenticates as the mapped role and evaluates that role's attached S3 permissions. As a result, a valid OIDC user whose token would be denied the role through STS can obtain the role's S3 access, including object read, write, and delete, by presenting the raw OIDC JWT directly to the S3 API. This issue is fixed in version 4.40

The advisory is available at github.com. This vulnerability was named CVE-2026-77298 since 08/20/2026. The exploitation appears to be easy. The attack can be initiated remotely. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1548.002 by the MITRE ATT&CK project.

Upgrading to version 4.40 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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
• 4.24
• 4.25
• 4.26
• 4.27
• 4.28
• 4.29
• 4.30
• 4.31
• 4.32
• 4.33
• 4.34
• 4.35
• 4.36
• 4.37
• 4.38
• 4.39

Website

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

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