OpenBao’s handleLogicalRecovery endpoint performed a straightforward string comparison between a highly privileged recovery token and the supplied token, causing the duration of the comparison to vary depending on the input. A remote attacker who can trigger repeated recovery mode requests can measure the response times and infer the correct token through a timing side‑channel. Once the token is discovered, the attacker gains full authorization to perform recovery mode operations, which can read or modify any data stored in OpenBao.

The vulnerability affects OpenBao deployments running any version prior to 2.6.0. The issue was fixed in version 2.6.0, so any installation using an earlier major or minor release is vulnerable.

The CVSS vector scores this flaw 9.2, indicating a high severity. No EPSS score is available, but the lack of authentication for the recovery endpoint makes exploitation straightforward. Because the attacker only needs to send HTTP requests to the logical recovery path, an unauthenticated remote attacker could easily mount the timing attack. The vulnerability is not listed in CISA’s KEV catalog, but the impact scope – full data exposure and modification – makes it a critical risk for exposed OpenBao services.