How severe is CVE-2024-21538?

No CVSS score has been assigned to CVE-2024-21538 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-21538?

CVE-2024-21538 affects the following packages: cross-spawn (npm), cross-spawn (npm). Ecosystems affected: npm.

How do I fix CVE-2024-21538?

Update cross-spawn to 7.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21538 is resolved across your whole dependency graph.

How do I detect CVE-2024-21538 in my npm dependencies?

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

How do I mitigate CVE-2024-21538 if there is no patch (or I can't update yet)?

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.

Is CVE-2024-21538 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-21538 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-21538?

CVE-2024-21538 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th 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-2024-21538?

CVE-2024-21538 is classified as CWE-1333 (CWE-1333). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-21538 published, and has it been updated?

CVE-2024-21538 was published on November 8, 2024 and was last updated on October 28, 2026. 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

CVE-2024-21538 — cross-spawn

Fix: moxystudio/node-cross-spawn@5ff3a07

CVE-2024-21538 is a CWE-1333 vulnerability in cross-spawn. A fix is available for cross-spawn — see the affected versions and patch details below.

Regular Expression Denial of Service (ReDoS) in cross-spawn

Also known asGHSA-3xgq-45jj-v275

Published

Nov 8, 2024

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-21538.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

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

Real-World Exposure

2 pkgs 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.

12Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

cross-spawnnpm

342.8Mdownloads / week

Description

Versions of the package cross-spawn before 6.0.6, from 7.0.0 and before 7.0.5 are vulnerable to Regular Expression Denial of Service (ReDoS) due to improper input sanitization. An attacker can increase the CPU usage and crash the program by crafting a very large and well crafted string.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`cross-spawn`	≥ 7.0.0&&< 7.0.5	7.0.5`npm install cross-spawn@7.0.5`
📦npm	`cross-spawn`	all versions	6.0.6`npm install cross-spawn@6.0.6`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cross-spawn, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cross-spawn to 7.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21538 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.

Red HatLow

Product	Fixed in	Advisory
Discovery 1 for RHEL 9	`discovery/discovery-server-rhel9:1.12.0-1`	RHSA-2025:1249
Red Hat Advanced Cluster Security 4.4	`advanced-cluster-security/rhacs-main-rhel8:4.4.7-2`	RHSA-2024:10665
Red Hat Advanced Cluster Security 4.5	`advanced-cluster-security/rhacs-main-rhel8:4.5.5-3`	RHSA-2024:10186
Red Hat Developer Hub 1.3 on RHEL 9	`rhdh/rhdh-hub-rhel9:1.3-131`	RHBA-2024:10760
Red Hat Migration Toolkit for Containers 1.8	`rhmtc/openshift-migration-ui-rhel8:v1.8.7-2`	RHSA-2025:8510
Red Hat OpenShift Container Platform 4.14	`openshift4/ose-monitoring-plugin-rhel8:v4.14.0-202412040905.p0.g4fa7043.assembly.stream.el8`	RHSA-2024:11031
Red Hat OpenShift Container Platform 4.15	`openshift4/ose-monitoring-plugin-rhel8:v4.15.0-202412041605.p0.g1217bc1.assembly.stream.el8`	RHSA-2024:10839
Red Hat OpenShift Container Platform 4.16	`openshift4/ose-monitoring-plugin-rhel9:v4.16.0-202412040032.p0.g6cfc2c8.assembly.stream.el9`	RHSA-2024:10823

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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