CVE-2017-20162 is a medium-severity (CVSS 5.3) CWE-1333 vulnerability in ms. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for ms — see the affected versions and patch details below.
Vercel ms Inefficient Regular Expression Complexity vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2017-20162.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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.
msnpmDescription
A vulnerability, which was classified as problematic, has been found in vercel ms up to 1.x. This issue affects the function parse of the file index.js. The manipulation of the argument str leads to inefficient regular expression complexity. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 2.0.0 is able to address this issue. The name of the patch is caae2988ba2a37765d055c4eee63d383320ee662. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-217451.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ms | all versions | 2.0.0npm install ms@2.0.0 |
Affected Products
msvercelResearch 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 ms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ms to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-20162 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.
Frequently Asked Questions
Is CVE-2017-20162 in your dependencies?
Find it across npm, including transitive dependencies.