CVE-2018-7750 is a critical-severity (CVSS 9.8) Improper Authentication vulnerability in paramiko. 4 public exploit references exist, so weaponization risk is real. A fix is available for paramiko — see the affected versions and patch details below.
Paramiko not properly checking authentication before processing other requests
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-2018-7750 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 377,636 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
paramiko🐍paramiko🐍paramiko🐍paramiko🐍paramiko🐍paramiko🐍paramikoReal-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
transport.py in the SSH server implementation of Paramiko before 1.17.6, 1.18.x before 1.18.5, 2.0.x before 2.0.8, 2.1.x before 2.1.5, 2.2.x before 2.2.3, 2.3.x before 2.3.2, and 2.4.x before 2.4.1 does not properly check whether authentication is completed before processing other requests, as demonstrated by channel-open. A customized SSH client can simply skip the authentication step.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | paramiko | ≥ 2.0.0&&< 2.0.8 | 2.0.8pip install --upgrade 'paramiko==2.0.8' |
| 🐍PyPI | paramiko | ≥ 2.1.0&&< 2.1.5 | 2.1.5pip install --upgrade 'paramiko==2.1.5' |
| 🐍PyPI | paramiko | ≥ 2.2.0&&< 2.2.3 | 2.2.3pip install --upgrade 'paramiko==2.2.3' |
| 🐍PyPI | paramiko | ≥ 2.3.0&&< 2.3.2 | 2.3.2pip install --upgrade 'paramiko==2.3.2' |
| 🐍PyPI | paramiko | ≥ 2.4.0&&< 2.4.1 | 2.4.1pip install --upgrade 'paramiko==2.4.1' |
| 🐍PyPI | paramiko | ≥ 1.18.0&&< 1.18.5 | 1.18.5pip install --upgrade 'paramiko==1.18.5' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Paramiko 2.4.1 - Authentication Bypass
by Adam Brown · Oct 29, 2018
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for paramiko, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update paramiko to 2.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-7750 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-2018-7750 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-7750. 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.
This flaw is a user authentication bypass in the SSH Server functionality of paramiko (normally used by subclassing `paramiko.ServerInterface`). Where paramiko is used only for its client-side functionality (e.g. `paramiko.SSHClient`), the vulnerability is not exposed and thus cannot be exploited. The following Red…
| Product | Fixed in | Advisory |
|---|---|---|
| CloudForms Management Engine 5.8 | ansible-0:2.4.4.0-1.el7ae | RHSA-2018:1972 |
| CloudForms Management Engine 5.9 | ansible-0:2.4.4.0-1.el7ae | RHSA-2018:1328 |
| Red Hat Ansible Engine 2.4 for RHEL 7 | python-paramiko-0:2.1.1-4.el7 | RHSA-2018:1213 |
| Red Hat Ansible Engine 2 for RHEL 7 | python-paramiko-0:2.1.1-4.el7 | RHSA-2018:0646 |
| Red Hat Enterprise Linux 6 | python-paramiko-0:1.7.5-4.el6_9 | RHSA-2018:1124 |
| Red Hat Enterprise Linux 6.4 Advanced Update Support | python-paramiko-0:1.7.5-4.el6_4 | RHSA-2018:1125 |
| Red Hat Enterprise Linux 7 Extras | python-paramiko-0:2.1.1-4.el7 | RHSA-2018:0591 |
| Red Hat Virtualization 4 for Red Hat Enterprise Linux 7 | python-paramiko-0:2.1.1-4.el7 | RHSA-2018:1274 |
Frequently Asked Questions
Is CVE-2018-7750 in your dependencies?
O3 Security finds CVE-2018-7750 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.