Cyber Resilience

CVE-2021-38155

HighPublic PoC

Published: 06 August 2021

Published
06 August 2021
Modified
21 November 2024
KEV Added
Patch
10 August 2021
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0107 78.1th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-38155 is a high-severity Improper Restriction of Excessive Authentication Attempts (CWE-307) vulnerability in Openstack Keystone. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 21.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

openstack
keystone
10.0.0 — 16.0.2 · 17.0.0 — 17.0.1 · 18.0.0 — 18.0.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-307

This control directly enforces limits on consecutive invalid logon attempts and automatic response (e.g., lockout) to prevent brute-force exploitation of authentication mechanisms.

addresses: CWE-307

Specific conditions can include excessive failed attempts, triggering stronger authentication that restricts brute-force exploitation.

References