How severe is CVE-2021-24033?

CVE-2021-24033 has a CVSS score of 5.6/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-24033?

CVE-2021-24033 affects the following packages: react-dev-utils (npm). Ecosystems affected: npm.

How do I fix CVE-2021-24033?

Update react-dev-utils to 11.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-24033 is resolved across your whole dependency graph.

How do I detect CVE-2021-24033 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-dev-utils, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-24033 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2021-24033 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-24033, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-24033?

CVE-2021-24033 has an EPSS (Exploit Prediction Scoring System) score of 3.3%, placing it in the 88th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-24033?

CVE-2021-24033 is classified as OS Command Injection (CWE-78). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-24033 published, and has it been updated?

CVE-2021-24033 was published on March 11, 2021 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2021-24033 — react-dev-utils

MEDIUMFix: facebook/create-react-app#10644

CVE-2021-24033 is a medium-severity (CVSS 5.6) OS Command Injection vulnerability in react-dev-utils. 1 public exploit reference exists, so weaponization risk is real. A fix is available for react-dev-utils — see the affected versions and patch details below.

react-dev-utils OS Command Injection in function `getProcessForPort`

Published

Mar 11, 2021

Updated

Nov 8, 2023

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Oct 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs88th percentile — riskier than 88% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-24033 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

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.

6Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

react-dev-utilsnpm

5.0Mdownloads / week

Description

react-dev-utils prior to v11.0.4 exposes a function, getProcessForPort, where an input argument is concatenated into a command string to be executed. This function is typically used from react-scripts (in Create React App projects), where the usage is safe. Only when this function is manually invoked with user-provided values (ie: by custom code) is there the potential for command injection. If you're consuming it from react-scripts then this issue does not affect you.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`react-dev-utils`	≥ 0.4.0&&< 11.0.4	11.0.4`npm install react-dev-utils@11.0.4`

Affected Products

1 product · 1 configurations

Application

react-dev-utilsfacebook

< 11.0.4

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

react-dev-utils prior to v11.0.4 exposes a function, getProcessForPort, …

github.comNVDMar 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-dev-utils, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update react-dev-utils to 11.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-24033 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

react-dev-utils prior to v11.0.4 exposes a function, `getProcessForPort`, where an input argument is concatenated into a command string to be executed. This function is typically used from react-scripts (in Create React App projects), where the usage is safe. Only when this function is manually invoked with user-provided values (ie: by custom code) is there the potential for command injection. If you're consuming it from react-scripts then this issue does not affect you.

O3 Security · Impact-Aware SCA

Is CVE-2021-24033 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.6/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

CWE Classification

CWE-78OS Command Injection

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

create-react-app

4.8/10

Maintained0/10

Code-Review7/10

Branch-ProtectionN/A

Assessed Oct 5, 2026

Timeline

Disclosed

Mar 11, 2021

First exploit

Mar 16, 2021

5 days after disclosure — rapid exploitation

Last updated

Nov 8, 2023

Identifiers

CVE-2021-24033

References

Advisorynvd.nist.gov Webgithub.com Webgithub.com Webfacebook.com Webhuntr.dev Packagegithub.com

Related vulnerabilities

Also affects react-dev-utils

This CVE is medium severity; 1 of 1 other CVE affecting react-dev-utils is rated as high or higher (top: high).

CVE-2018-6342

Same weakness: CWE-78

This CVE is medium severity; 7 of 7 other CVEs with CWE-78 are rated as high or higher (top: critical).

CVE-2026-85756CVE-2026-71538CVE-2026-59960CVE-2026-84361CVE-2026-73294CVE-2026-73222CVE-2026-73667Browse all CWE-78

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedNov 8, 2023