CVE-2021-38155 — keystone
HIGHCVE-2021-38155 is a high-severity (CVSS 7.5) CWE-307 vulnerability in keystone. 1 public exploit reference exists, so weaponization risk is real. A fix is available for keystone — see the affected versions and patch details below.
OpenStack Keystone allows information disclosure during account locking
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2021-38155 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
keystone🐍keystone🐍keystone🐍keystoneReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | keystone | ≥ 10.0&&< 16.0.2 | 16.0.2pip install --upgrade 'keystone==16.0.2' |
| 🐍PyPI | keystone | ≥ 17.0&&< 17.0.1 | 17.0.1pip install --upgrade 'keystone==17.0.1' |
| 🐍PyPI | keystone | ≥ 18.0&&< 18.0.1 | 18.0.1pip install --upgrade 'keystone==18.0.1' |
| 🐍PyPI | keystone | ≥ 19.0&&< 19.0.1 | 19.0.1pip install --upgrade 'keystone==19.0.1' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for keystone, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update keystone to 16.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-38155 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-38155 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-38155. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-38155 in your dependencies?
O3 Security finds CVE-2021-38155 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.