An argument processing flaw can cause Buffer.alloc() to return uninitialized memory. This method is intended to be safe and only return initialized, or cleared, memory. The third argument…

Exploitation

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

CVSS

not scored

EPSS

• CVE-2018-7166: 3.29% estimated exploitation activity in the next 30 days; percentile 88.50 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

An argument processing flaw can cause `Buffer.alloc()` to return uninitialized memory. This method is intended to be safe and only return initialized, or cleared, memory. The third argument specifying `encoding` can be passed as a number, this is misinterpreted by `Buffer's` internal "fill" method as the `start` to a fill operation. This flaw may be abused where `Buffer.alloc()` arguments are derived from user input to return uncleared memory blocks that may contain sensitive information.

Published by the source

15 Aug 2018, 00:00 UTC

Last modified by the source

15 Aug 2018, 00:00 UTC

Source last checked

26 Oct 2026, 16:35 UTC

1. Revision 2 · published · 26 Oct 2026

   Published from vendor_advisory record nodejs-security-wg:core:53

2. Revision 1 · created · 26 Oct 2026

   Created from vendor_advisory record nodejs-security-wg:core:53

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# Patch Next advisory brief: CVE-2018-7166

Advisory: An argument processing flaw can cause `Buffer.alloc()` to return uninitialized memory. This method is intended to be safe and only return initialized, or cleared, memory. The third argument…
IDs: CVE-2018-7166
Record: https://patchnext.com/advisories/cve-2018-7166 (revision 2, source checked 26 Oct 2026, 16:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: node 10.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- runtime node: affected >= 10.0.0, < 10.9.0; fixed in 10.9.0

## Suggested inspection (read-only)
- runtime node: check the installed version with your package manager.

## 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 node.
- 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://raw.githubusercontent.com/nodejs/security-wg/main/vuln/core/53.json (Node.js security working group core entry 53 lists CVE-2018-7166 affecting node >=10.0.0 <10.9.0)
- Verified: https://nodejs.org/dist/index.json (The nodejs.org release index dates the first patched release for CVE-2018-7166 to 2018-08-15.)

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