CVE-2026-77298: high-severity vulnerability in seaweedfs
SeaweedFS S3 OIDC Bearer authentication bypasses IAM role trust policy
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.4%
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
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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%