Headline
GHSA-rxp7-9q75-vj3p: OpenBao Login MFA Bypass of Rate Limiting and TOTP Token Reuse
Impact
OpenBao’s Login Multi-Factor Authentication (MFA) system allows enforcing MFA using Time-based One Time Password (TOTP). Due to normalization applied by the underlying TOTP library, codes were accepted which could contain whitespace; this whitespace could bypass internal rate limiting of the MFA method and allow reuse of existing MFA codes.
Patches
OpenBao v2.3.2 will patch this issue.
Workarounds
Use of rate-limiting quotas can limit an attacker’s ability to exploit this: https://openbao.org/api-docs/system/rate-limit-quotas/
References
This issue was disclosed to HashiCorp and is the OpenBao equivalent of the following tickets:
- https://discuss.hashicorp.com/t/hcsec-2025-19-vault-login-mfa-bypass-of-rate-limiting-and-totp-token-reuse/76038
- https://nvd.nist.gov/vuln/detail/CVE-2025-6015
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.