OpenBao versions 2.3.0 through 2.6.3 contain an incorrect authorization flaw (CWE-863) in the ACL policy cache that allows a token holder to reference policies in arbitrary namespaces by using specially crafted policy names. This enables the attacker to obtain the capabilities of cached policies from other namespaces, including the root namespace, effectively extending the reach of the token beyond its intended scope. The flaw permits actions that the attacker would otherwise be barred from, compromising confidentiality and integrity of resources across namespaces.

Products affected are all instances of OpenBao from version 2.3.0 up to but not including 2.6.3. No other vendors or products are listed as affected.

The vulnerability scores a CVSS 7.5, indicating a high severity. EPSS data is not available, and the vulnerability is not currently listed in CISA’s KEV catalog. Attackers need only a valid token and the ability to craft a policy name to exploit the cache traversal. Because the flaw is in the authorization mechanism, it can be leveraged in most regular deployment scenarios where tokens are issued and policies are cached. The attack vector is a local or remote request using a legitimate token to access an unintended namespace.