CVE-2021-38155

Exp

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.

Published: 2021-08-06 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-38155 is rated High Exploit Risk (75.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.46%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.39% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-38155

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-38155

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.07% 2.46% +1.39%
2 2026-06-06 0.74% 1.07% +0.33%
3 2026-03-20 — 0.74% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38155

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-38155

GitHub Security Advisory for CVE-2021-38155

GHSA-4225-97pr-rr52 · Severity: high · Ecosystem: pip — OpenStack Keystone allows information disclosure during account locking

OS Trackers for CVE-2021-38155

vendor priority summary link
debian not yet assigned CVE-2021-38155 not yet assigned priority: Debian including 1 source packages (keystone), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-38155
suse high CVE-2021-38155 severity important: SUSE including 83 source package names (ardana-barbican-9.0+git.1644879908.8a641c1-3.13.1, documentation-hpe-helion-openstack-installation-8.20211112-1.38.1, …), 140 product×package rows across 5 product lines (HPE Helion OpenStack 8, SUSE OpenStack Cloud 8, … (5 product lines)): Fixed 140. https://www.suse.com/security/cve/CVE-2021-38155/
ubuntu low CVE-2021-38155 low priority: Ubuntu including 1 source packages (keystone), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 6, needs-triage 4, not-affected 4, DNE 1. https://ubuntu.com/security/CVE-2021-38155

Affected software / configurations for CVE-2021-38155

Vendor Product Version Raw CPE
openstack keystone >= 10.0.0, < 16.0.2 cpe:2.3:a:openstack:keystone:*:*:*:*:*:*:*:*
openstack keystone >= 17.0.0, < 17.0.1 cpe:2.3:a:openstack:keystone:*:*:*:*:*:*:*:*
openstack keystone >= 18.0.0, < 18.0.1 cpe:2.3:a:openstack:keystone:*:*:*:*:*:*:*:*
openstack keystone >= 19.0.0, < 19.0.1 cpe:2.3:a:openstack:keystone:*:*:*:*:*:*:*:*

References for CVE-2021-38155

cvelogic Threat Intelligence