CVE-2017-16191 — cypserver
HIGHCVE-2017-16191 is a high-severity (CVSS 7.5) Path Traversal vulnerability in cypserver. 1 public exploit reference exists, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.
Directory Traversal in cypserver
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2017-16191 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
cypservernpmDescription
Affected versions of cypserver resolve relative file paths, resulting in a directory traversal vulnerability. A malicious actor can use this vulnerability to access files outside of the intended directory root, which may result in the disclosure of private files on the vulnerable system.
Example request:
GET /../../../../../../../../../../etc/passwd HTTP/1.1
host:foo
Recommendation
No patch is available for this vulnerability.
It is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | cypserver | ≥ 0.0.0 | No fix |
Affected Products
cypservercypserver_projectResearch 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 cypserver, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of cypserver has shipped for CVE-2017-16191 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2017-16191 in your dependencies?
Find it across npm, including transitive dependencies.