CVE-2021-23440 is a critical-severity (CVSS 9.8) CWE-843 vulnerability in set-value. 3 public exploit references exist, so weaponization risk is real. A fix is available for set-value — see the affected versions and patch details below.
Prototype Pollution in set-value
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-23440 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
set-valuenpmDescription
This affects the package set-value before <2.0.1, >=3.0.0 <4.0.1. 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | set-value | ≥ 4.0.0&&< 4.0.1 | 4.0.1npm install set-value@4.0.1 |
| 📦npm | set-value | all versions | 2.0.1npm install set-value@2.0.1 |
| 📦npm | set-value | ≥ 3.0.0&&< 3.0.3 | 3.0.3npm install set-value@3.0.3 |
| .NETNuGet | set-value-nuget | all versions | 2.0.0dotnet add package set-value-nuget --version 2.0.0 |
Affected Products
communications cloud native core policyoracleset-valueset-value_projectResearch 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 set-value, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update set-value to 4.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23440 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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Data Foundation 4.11 on RHEL8 | odf4/mcg-core-rhel8:v4.11.0-30 | RHSA-2022:6156 |
Frequently Asked Questions
Is CVE-2021-23440 in your dependencies?
Find it across npm, NuGet, including transitive dependencies.