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

Low severity GitHub Reviewed Published Aug 8, 2025 in openbao/openbao • Updated Aug 11, 2025

Package

gomod github.com/openbao/openbao (Go)

Affected versions

>= 0.1.0, < 2.3.2
< 0.0.0-20250806193356-4d9b5d3d6486

Patched versions

2.3.2
0.0.0-20250806193356-4d9b5d3d6486

Description

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:

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

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.

References

@cipherboy cipherboy published to openbao/openbao Aug 8, 2025
Published to the GitHub Advisory Database Aug 8, 2025
Reviewed Aug 8, 2025
Published by the National Vulnerability Database Aug 9, 2025
Last updated Aug 11, 2025

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(5th percentile)

Weaknesses

Observable Discrepancy

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not. Learn more on MITRE.

CVE ID

CVE-2025-54999

GHSA ID

GHSA-hh28-h22f-8357

Source code

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