CVE-2020-8163 — actionview
HIGHCVE-2020-8163 is a high-severity (CVSS 8.8) Code Injection vulnerability in actionview. 6 public exploit references exist, so weaponization risk is real. A fix is available for actionview — see the affected versions and patch details below.
Remote code execution via user-provided local names in ActionView
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-2020-8163 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
actionviewReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
The is a code injection vulnerability in versions of Rails prior to 5.0.1 that wouldallow an attacker who controlled the locals argument of a render call to perform a RCE.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | actionview | all versions | 4.2.11.3bundle update actionview --conservative |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Rails 5.0.1 - Remote Code Execution
by Lucas Amorim · Jul 26, 2020
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for actionview, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update actionview to 4.2.11.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-8163 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-2020-8163 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2020-8163. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
How to detect CVE-2020-8163
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2020-8163 -u https://target- Template
- Ruby on Rails <5.0.1 - Remote Code Execution
- Severity
- high
- Impact
- Successful exploitation of this vulnerability can lead to unauthorized remote code execution.
- Remediation
- Upgrade Ruby on Rails to version 5.0.1 or above.
Template by ProjectDiscovery nuclei-templates (tim_koopmans), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2020-8163 in your dependencies?
O3 Security finds CVE-2020-8163 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.