CVE-2021-3749 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in axios. 1 public exploit reference exists, so weaponization risk is real. A fix is available for axios — see the affected versions and patch details below.
axios Inefficient Regular Expression Complexity vulnerability
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-3749 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 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.
axiosnpmDescription
axios before v0.21.2 is vulnerable to Inefficient Regular Expression Complexity.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | axios | all versions | 0.21.2npm install axios@0.21.2 |
Affected Products
axiosaxiosgoldengateoraclesinec inssiemensResearch 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 axios, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update axios to 0.21.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-3749 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.
* OpenShift Container Platform (OCP) grafana-container does package a vulnerable version of nodejs axios. However, due to the instance being read only and behind OpenShift OAuth, the impact of this vulnerability is Low. * Red Hat Advanced Cluster Management for Kubernetes (RHACM) 2.1 and previous versions does contain…
| Product | Fixed in | Advisory |
|---|---|---|
| Migration Toolkit for Virtualization 2.2 | migration-toolkit-virtualization/mtv-ui-rhel8:2.2.0-60 | RHEA-2021:5066 |
| OpenShift Service Mesh 2.0 | kiali-0:v1.24.7.redhat1-1.el8 | RHSA-2022:1276 |
| Red Hat Migration Toolkit for Containers 1.6 | rhmtc/openshift-migration-ui-rhel8:v1.6.0-24 | RHSA-2021:3694 |
| Red Hat OpenShift Container Platform 4.10 | openshift4/ose-console:v4.10.0-202202240423.p0.gb6503ff.assembly.stream | RHSA-2022:0056 |
| RHACS-3.67-RHEL-8 | advanced-cluster-security/rhacs-rhel8-operator:3.67.0-3 | RHSA-2021:4902 |
Frequently Asked Questions
Is CVE-2021-3749 in your dependencies?
Find it across npm, including transitive dependencies.