CVE-2016-10549 is a medium-severity (CVSS 4.4) CWE-284 vulnerability in sails. A fix is available for sails — see the affected versions and patch details below.
Sails before 0.12.7 vulnerable to Broken CORS
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-2016-10549 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% 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, and reverse-dependency count shows how many other packages break if it stays unpatched.
sailsnpmDescription
Affected versions of sails have an issue with the CORS configuration where the value of the origin header is reflected as the value for the Access-Control-Allow-Origin header. This may allow an attacker to make AJAX requests to vulnerable hosts through cross-site scripting or a malicious HTML Document, effectively bypassing the Same Origin Policy.
Mitigating Factors
This is only an issue when allRoutes is set to true and origin is set to * or left commented out in the sails CORS config file.
The problem can be compounded when the cors credentials setting is not provided, because at that point authenticated cross domain requests are possible.
Recommendation
Update to version 0.12.7 or later.
As this vulnerability is primarily a user error, the patch for the vulnerability will simply cause the application to write an error message to the console when a vulnerable configuration is used in a production environment.
Writing a proper CORS configuration is still the responsibility of the user, so it is necessary to check for the error message after installing the patch. Be sure you are not using allRoutes: true with origin:'*', and that you uncomment origin and set it to a reasonable value. Ensure that if origin is set to * that you truly mean for all other websites to be able to make cross-domain requests to your API.
Likewise, ensure credentials is uncommented out and set to the appropriate value. Make sure to explicitly set which origins may request resources via CORS.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | sails | all versions | 0.12.7npm install sails@0.12.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sails, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sails to 0.12.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-10549 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-2016-10549 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2016-10549. 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-2016-10549 in your dependencies?
O3 Security finds CVE-2016-10549 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.