CVE-2020-15366 is a medium-severity (CVSS 5.6) CWE-1321 vulnerability in ajv. A fix is available for ajv — see the affected versions and patch details below.
Prototype Pollution in Ajv
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-15366 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.
ajvnpmDescription
An issue was discovered in ajv.validate() in Ajv (aka Another JSON Schema Validator) 6.12.2. A carefully crafted JSON schema could be provided that allows execution of other code by prototype pollution. (While untrusted schemas are recommended against, the worst case of an untrusted schema should be a denial of service, not execution of code.)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ajv | all versions | 6.12.3npm install ajv@6.12.3 |
Affected Products
ajvajv.jsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ajv, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ajv to 6.12.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15366 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
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.
In both OpenShift Container Platform (OCP) and OpenShift ServiceMesh (OSSM), the affected containers are behind OpenShift OAuth authentication. This restricts access to the vulnerable nodejs-ajv library to authenticated users only, therefore the impact is low.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Automation Hub 4.2 for RHEL 7 | automation-hub-0:4.2.2-1.el7pc | RHSA-2021:0781 |
| Red Hat Enterprise Linux 8 | nodejs:12-8030020201124152102.229f0a1c | RHSA-2020:5499 |
| Red Hat Enterprise Linux 8 | nodejs:10-8030020210118191659.229f0a1c | RHSA-2021:0548 |
| Red Hat Enterprise Linux 8 | nodejs:14-8030020210126165503.229f0a1c | RHSA-2021:0551 |
| Red Hat OpenShift Container Platform 4.6 | openshift4/ose-console:v4.6.0-202010100121.p0 | RHSA-2020:4298 |
| Red Hat Quay 3 | quay/quay-rhel8:v3.6.0-62 | RHSA-2021:3917 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-nodejs12-nodejs-0:12.19.1-2.el7 | RHSA-2020:5305 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-nodejs14-nodejs-0:14.15.4-2.el7 | RHSA-2021:0421 |
Frequently Asked Questions
Is CVE-2020-15366 in your dependencies?
Find it across npm, including transitive dependencies.