CVE-2018-16859 is a medium-severity (CVSS 4.4) CWE-532 vulnerability in ansible. A fix is available for ansible — see the affected versions and patch details below.
Ansible Logs Passwords If PowerShell ScriptBlock is Enabled
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-2018-16859 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 377,166 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
ansible🐍ansible🐍ansibleReal-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
Execution of Ansible playbooks on Windows platforms with PowerShell ScriptBlock logging and Module logging enabled can allow for 'become' passwords to appear in EventLogs in plaintext. A local user with administrator privileges on the machine can view these logs and discover the plaintext password. Ansible Engine 2.8 and older are believed to be vulnerable.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | ansible | ≥ 2.7.0a1&&< 2.7.3 | 2.7.3pip install --upgrade 'ansible==2.7.3' |
| 🐍PyPI | ansible | all versions | 2.5.12pip install --upgrade 'ansible==2.5.12' |
| 🐍PyPI | ansible | ≥ 2.6.0a1&&< 2.6.9 | 2.6.9pip install --upgrade 'ansible==2.6.9' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ansible, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ansible to 2.7.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-16859 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-2018-16859 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-16859. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
CloudForms and Satellite 6 are not affected by this issue, since Microsoft Windows is not a supported platform.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Engine 2.5 for RHEL 7 | ansible-0:2.5.13-1.el7ae | RHSA-2018:3770 |
| Red Hat Ansible Engine 2.6 for RHEL 7 | ansible-0:2.6.10-1.el7ae | RHSA-2018:3771 |
| Red Hat Ansible Engine 2.7 for RHEL 7 | ansible-0:2.7.4-1.el7ae | RHSA-2018:3773 |
| Red Hat Ansible Engine 2 for RHEL 7 | ansible-0:2.7.4-1.el7ae | RHSA-2018:3772 |
Frequently Asked Questions
Is CVE-2018-16859 in your dependencies?
O3 Security finds CVE-2018-16859 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.