CVE-2025-55003: OpenBao Login MFA Bypasses 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
Other sources
OpenBao exists to provide a software solution to manage, store, and distribute sensitive data including secrets, certificates, and keys. In versions 2.3.1 and below, 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. This issue was fixed in version 2.3.2. To work around this, use of rate-limiting quotas can limit an attacker's ability to exploit this: https://openbao.org/api-docs/system/rate-limit-quotas/.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-55003?
CVE-2025-55003 has a critical severity rating due to its capability to bypass authentication rate limiting.
How do I fix CVE-2025-55003?
To fix CVE-2025-55003, update OpenBao to version 0.0.0-20250807113757-8340a6918f6c or 2.3.2.
What impact does CVE-2025-55003 have on users?
CVE-2025-55003 may allow unauthorized access to user accounts by bypassing the Multi-Factor Authentication system.
Which versions of OpenBao are affected by CVE-2025-55003?
OpenBao versions prior to 0.0.0-20250807113757-8340a6918f6c and between 0.1.0 and 2.3.2 are affected by CVE-2025-55003.
Is there a known exploit for CVE-2025-55003?
Yes, there is a potential exploit for CVE-2025-55003 that allows attackers to bypass authentication mechanisms.