Executive brief
OpenStack Keystone, the identity service for OpenStack cloud environments, contains a flaw where restricted user credentials can be used to generate more powerful access keys. An attacker with limited, read-only access could exploit this to obtain full administrative control over object storage (S3/Swift) buckets. This bypasses security restrictions intended to limit what specific applications or users can do, potentially leading to unauthorized data modification or deletion.
Technical details
An incorrect authorization vulnerability (CWE-863) exists in Keystone's EC2 credential creation endpoint (POST /v3/users/{user_id}/credentials/OS-EC2). The endpoint fails to enforce application credential restrictions, allowing an authenticated user with a restricted 'reader' role to generate EC2/S3 credentials. These newly created credentials inherit the full permissions of the parent user rather than the restricted scope of the application credential. This exploit is specifically applicable to deployments using the EC2/S3 compatibility APIs (s3api/swift3). Patches have been released for multiple OpenStack release branches including Caracal, Dalmatian, and others.
Affected products
- OpenStack Keystone >= 14.0.0, < 26.1.1; 27.0.0; 28.0.0; 29.0.0
Timeline
- 2026-02-18: disclosed: Vulnerability reported to OpenStack Security Team
- 2026-04-07: advisory: OpenStack Security Advisory OSSA-2026-005 published
- 2026-04-10: advisory: CVE-2026-33551 published to NVD