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Vulnerability record · CVE-2021-38155 · published 6 August 2021

CVE-2021-38155: Openstack keystone improper restriction of authentication attempts vulnerability

Openstack · Keystone

OpenStack Keystone 10.x through 16.x before 16.0.2, 17.x before 17.0.1, 18.x before 18.0.1, and 19.x before 19.0.1 allows information disclosure during account locking (related to PCI DSS features). By guessing the name of an account and failing to authenticate multiple times, any unauthenticated actor could both confirm the account exists and obtain that account's corresponding UUID, which might be leveraged for other unrelated attacks. All deployments enabling security_compliance.lockout_failure_attempts are affected.

7.5 CVSS 3.1 High EPSS 2.5% · top 16.1% CWE-307 · Improper restriction of authentication attempts
7.5CVSS 3.1 base score, v2 5.0
2.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

OpenStack Keystone 10.x through 16.x before 16.0.2, 17.x before 17.0.1, 18.x before 18.0.1, and 19.x before 19.0.1 allows information disclosure during account locking (related to PCI DSS features). By guessing the name of an account and failing to authenticate multiple times, any unauthenticated actor could both confirm the account exists and obtain that account's corresponding UUID, which might be leveraged for other unrelated attacks. All deployments enabling security_compliance.lockout_failure_attempts are affected.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.openwall.com/lists/oss-security/2021/08/10/5 Mailing ListPatchThird Party Advisory
https://launchpad.net/bugs/1688137 ExploitIssue TrackingPatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00007.html
https://security.openstack.org/ossa/OSSA-2021-003.html PatchVendor Advisory
http://www.openwall.com/lists/oss-security/2021/08/10/5 Mailing ListPatchThird Party Advisory
https://launchpad.net/bugs/1688137 ExploitIssue TrackingPatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2024/01/msg00007.html
https://security.openstack.org/ossa/OSSA-2021-003.html PatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2026-42998Openstack keystone incorrect authorization vulnerabilityAn issue was discovered in OpenStack Keystone before 29.0.2. The Keystone application credential authentication plugin does not verify that the user …EPSS 0.40%8.8CVE-2026-42999Openstack keystone incorrect authorization vulnerabilityAn issue was discovered in OpenStack Keystone before 29.0.2. The Keystone RBAC policy enforcer in enforce_call unconditionally merges the raw JSON re…EPSS 0.42%8.8CVE-2026-43000Openstack keystone incorrect authorization vulnerabilityAn issue was discovered in OpenStack Keystone before 29.0.2. When combined with an application credential impersonation vulnerability, an attacker wi…EPSS 0.43%8.8CVE-2020-12689Openstack keystone improper privilege management vulnerabilityAn issue was discovered in OpenStack Keystone before 15.0.1, and 16.0.0. Any user authenticated within a limited scope (trust/oauth/application crede…EPSS 1.6%8.8CVE-2020-12690Openstack keystone insufficient session expiration vulnerabilityAn issue was discovered in OpenStack Keystone before 15.0.1, and 16.0.0. The list of roles provided for an OAuth1 access token is silently ignored. T…EPSS 1.9%8.8CVE-2020-12691Openstack keystone incorrect authorization vulnerabilityAn issue was discovered in OpenStack Keystone before 15.0.1, and 16.0.0. Any authenticated user can create an EC2 credential for themselves for a pro…EPSS 4.9%8.8CVE-2019-19687Openstack keystone insufficiently protected credentials vulnerabilityOpenStack Keystone 15.0.0 and 16.0.0 is affected by Data Leakage in the list credentials API. Any user with a role on a project is able to list any c…EPSS 1.8%8.1CVE-2026-44394Openstack keystone incorrect authorization vulnerabilityAn issue was discovered in OpenStack Keystone before 29.0.2. The Keystone federated token rescoping mechanism does not propagate the original token's…EPSS 0.32%

Source: NIST National Vulnerability Database (record CVE-2021-38155), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.