OpenBao has a Timing Side-Channel in the Userpass Auth Method

Impact

When using OpenBao's userpass auth method, user enumeration was possible due to timing difference between non-existent users and users with stored credentials. This is independent of whether the supplied credentials were valid for the given user.

Patches

OpenBao v2.3.2 will patch this issue.

Workarounds

Users may use another auth method or apply rate limiting quotas to limit the number of requests in a period of time: 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-2025-15-timing-side-channel-in-vault-s-userpass-auth-method/76034
• https://nvd.nist.gov/vuln/detail/CVE-2025-6011

Barring further information, this is also assumed to cover and remediate the following additional vulnerability:

• https://discuss.hashicorp.com/t/hcsec-2025-21-vault-user-enumeration-in-userpass-auth-method/76095
• https://nvd.nist.gov/vuln/detail/CVE-2025-6010

If this is not the case as further details emerge, a new CVE will be assigned for remediating that. Otherwise, no further CVE will be sought.