Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 7.3amended

Prototype Pollution in set-value

CVE-2021-23440GHSA-4jqc-8m5r-9rpr

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (set-value 4.0.1, 3.0.3, 2.0.1; set-value-nuget 2.0.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • npm set-value

    Affected
    < 2.0.1>= 4.0.0, < 4.0.1>= 3.0.0, < 3.0.3
    Fixed in
    2.0.1, 3.0.3, 4.0.1

  • NuGet set-value-nuget

    Affected
    < 2.0.0
    Fixed in
    2.0.0

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS
  • CVE-2021-23440: 2.21% estimated exploitation activity in the next 30 days; percentile 82.59 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

This affects the package set-value. A type confusion vulnerability can lead to a bypass of CVE-2019-10747 when the user-provided keys used in the path parameter are arrays.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-4jqc-8m5r-9rpr

  2. Revision 1 · created ·

    Published from osv record GHSA-4jqc-8m5r-9rpr

Agent brief

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

# Patch Next advisory brief: CVE-2021-23440

Advisory: Prototype Pollution in set-value
IDs: CVE-2021-23440, GHSA-4jqc-8m5r-9rpr
Record: https://patchnext.com/advisories/cve-2021-23440 (revision 2, source checked 26 Oct 2026, 12:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: set-value 4.0.1, 3.0.3, 2.0.1; set-value-nuget 2.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm set-value: affected < 2.0.1; >= 4.0.0, < 4.0.1; >= 3.0.0, < 3.0.3; fixed in 2.0.1, 3.0.3, 4.0.1
- NuGet set-value-nuget: affected < 2.0.0; fixed in 2.0.0

## Suggested inspection (read-only)
- `npm ls set-value --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- NuGet set-value-nuget: 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 set-value, set-value-nuget.
- 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-4jqc-8m5r-9rpr (OSV record GHSA-4jqc-8m5r-9rpr lists affected ranges: npm set-value >=4.0.0 =0 =3.0.0 =0 <2.0.0 (fixed))
- Verified: https://github.com/advisories/GHSA-4jqc-8m5r-9rpr (GitHub-reviewed advisory GHSA-4jqc-8m5r-9rpr lists affected ranges: NuGet set-value-nuget >=0 =0 =4.0.0 =3.0.0 <3.0.3)

Commands are suggestions: review each one before running it.

Loading voting…