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

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

Severity from

GitHub (reviewed advisory)

Weakness

CWE-307

Also known as

BIT-openbao-2025-55003, CVE-2025-55003, GO-2025-3856

• github.com/openbao/openbao/security/advisories/GHSA-rxp7-9q75-vj3p
• nvd.nist.gov/vuln/detail/CVE-2025-55003
• nvd.nist.gov/vuln/detail/CVE-2025-6015
• github.com/openbao/openbao/commit/8340a6918f6c41d8f75b6c3845c376d9dc32ed19
• discuss.hashicorp.com/t/hcsec-2025-19-vault-login-mfa-bypass-of-rate-limiting-and-totp-token-reuse/76038
• github.com/openbao/openbao