OpenBao Login MFA Bypass of Rate Limiting and TOTP Token Reuse

MEDIUM 5.7CVE-2025-55003 · BIT-openbao-2025-55003 · GHSA-rxp7-9q75-vj3p · Published 09/08/2025 · updated 17/06/2026

In short

CVE-2025-55003 is a MEDIUM (CVSS 5.7) vulnerability affecting github.com/openbao/openbao, openbao (openbao).
Chance of exploitation in the next 30 days (EPSS): 0.27%, higher than 19.0% of all vulnerabilities.
Fix: update to 2.3.2, 0.0.0-20250807113757-8340a6918f6c or later.

Package	Affected versions	Patched versions
github.com/openbao/openbao Go	`≥ 0.1.0, < 2.3.2≥ 0.1.0< 0.0.0-20250807113757-8340a6918f6c`	`2.3.20.0.0-20250807113757-8340a6918f6c`
openbao openbao	`< 2.3.2`	`2.3.2`

Description

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:

NVD description

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/.