mcp-data-vis vulnerable to denial of service via unsanitized select key lookup on Object.prototype with precompile: true

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary icu-minify's runtime formatter resolves select branches by looking up the runtime value as a plain property on a prototype-bearing object. When the value coerces to a key that exists on Object.prototype (e.g. toString, proto, constructor, hasOwnProperty, valueOf), the lookup returns a truthy value that short-circuits the ?? options.other fallback, and the downstream iterator crashes with TypeError: nodes is not iterable. Any consumer that forwards user input into a {arg, select, …} placeholder — a common idiom for role, status, type, gender — can be crashed per-request by supplying one of those keys. In Next.js SSR (via next-intl with experimental.messages.precompile) this yields a 500 for the affected render. Details Vulnerable code paths Compilation produces a plain object whose prototype chain includes all Object.prototype members: At runtime, the formatter looks up the user-controllable value directly on that object: Because options inherits from Object.prototype, lookups…

Published by the source

6 May 2026, 17:32 UTC

Last modified by the source

6 May 2026, 17:48 UTC

Source last checked

26 Oct 2026, 12:51 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-r27j-894h-3w3p

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-r27j-894h-3w3p

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-r27j-894h-3w3p

Advisory: mcp-data-vis vulnerable to denial of service via unsanitized `select` key lookup on `Object.prototype` with `precompile: true`
IDs: GHSA-r27j-894h-3w3p
Record: https://patchnext.com/advisories/ghsa-r27j-894h-3w3p (revision 2, source checked 26 Oct 2026, 12:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: icu-minify 4.9.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm icu-minify: affected <= 4.9.1; fixed in 4.9.2

## Suggested inspection (read-only)
- `npm ls icu-minify --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on icu-minify.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-r27j-894h-3w3p (OSV record GHSA-r27j-894h-3w3p lists affected ranges: npm icu-minify >=0 <4.9.2 (fixed))
- Verified: https://github.com/advisories/GHSA-r27j-894h-3w3p (GitHub-reviewed advisory GHSA-r27j-894h-3w3p lists affected ranges: npm icu-minify >=0 <=4.9.1)

Commands are suggestions: review each one before running it.