CVE-2020-15123 is a critical-severity (CVSS 9.3) OS Command Injection vulnerability in codecov. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2020-15123 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Command injection in codecov (npm package)
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-2020-15123 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 0 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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
codecovnpmDescription
In codecov (npm package) before version 3.7.1 the upload method has a command injection vulnerability. Clients of the codecov-node library are unlikely to be aware of this, so they might unwittingly write code that contains a vulnerability. A similar CVE (CVE-2020-7597 for GHSA-5q88-cjfq-g2mh) was issued but the fix was incomplete. It only blocked &, and command injection is still possible using backticks instead to bypass the sanitizer. The attack surface is low in this case. Particularly in the standard use of codecov, where the module is used directly in a build pipeline, not built against as a library in another application that may supply malicious input and perform command injection.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | codecov | all versions | 3.7.1 |
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 codecov. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update codecov to 3.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15123 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 pinpoints whether CVE-2020-15123 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2020-15123. 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-2020-15123 in your dependencies?
O3 detects CVE-2020-15123 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.