CVE-2026-77298: Auth Bypass

Description

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

Is your site exposed to CVE-2026-77298?

Run a free security scan — no signup, results in seconds.

Weakness Type (CWE)

CWE-863 Incorrect Authorization

References

Other References

https://github.com/seaweedfs/seaweedfs/commit/ac524e140a37242b2488be9dfffae918da1d4de1 https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-757h-cm9x-wprg

Frequently Asked Questions

What is CVE-2026-77298? +

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

How do I check if I'm vulnerable to CVE-2026-77298? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-65601

Traefik versions 3.7.0 through 3.7.6 contain a namespace confusion vulnerability in the Kubernetes Gateway API provider. When resolving HTTPRoute.spec.rules[].backendRefs[].filters[].extensionRef, Traefik …

CVE-2026-50008

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. From version …

CVE-2026-15829

A SQL injection (CWE-89) and security boundary bypass (CWE-863) vulnerability exists in the prebuilt BigQuery forecasting tool (bigquery-forecast) of googleapis/mcp-toolbox. …

CVE-2026-42571

Pelican is a platform for creating data federations. From versions 7.21.0 to before 7.21.5, 7.22.0 to before 7.22.3, 7.23.0 to …

CVE-2026-42137

Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, `pages.access/list` and `files.access/list` permissions are not consistently …

CVE-2026-54358

An incorrect authorization vulnerability in MISP allows an organization administrator to target site administrator accounts belonging to the same organization …

CVE-2026-77298