How severe is CVE-2024-21505?

CVE-2024-21505 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2024-21505?

CVE-2024-21505 affects the following packages: web3-utils (npm). Ecosystems affected: npm.

How do I fix CVE-2024-21505?

Update web3-utils to 4.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21505 is resolved across your whole dependency graph.

How do I detect CVE-2024-21505 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for web3-utils, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-21505 if there is no patch (or I can't update yet)?

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.

Is CVE-2024-21505 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-21505 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-2024-21505?

CVE-2024-21505 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 53th 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-2024-21505?

CVE-2024-21505 is classified as CWE-1321 (CWE-1321). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-21505 published, and has it been updated?

CVE-2024-21505 was published on March 25, 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

HIGH severity

CVE-2024-21505 — web3-utils

HIGHFix: web3/web3.js@8ed041c

CVE-2024-21505 is a high-severity (CVSS 7.5) CWE-1321 vulnerability in web3-utils. A fix is available for web3-utils — see the affected versions and patch details below.

web3-utils Prototype Pollution vulnerability

Also known asGHSA-2g4c-8fpm-c46v

Published

Mar 25, 2024

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 26, 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-2024-21505.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs53th percentile — riskier than 53% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

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.

2Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

web3-utilsnpm

1.4Mdownloads / week

Description

Impact:

The mergeDeep() function in the web3-utils package has been identified for Prototype Pollution vulnerability. An attacker has the ability to modify an object's prototype, which could result in changing the behavior of all objects that inherit from the impacted prototype by providing carefully crafted input to function.

Patches:

It has been fixed in web3-utils version 4.2.1 so all packages and apps depending on web3-utils >=4.0.1 and <=4.2.0 should upgrade to web3-utils 4.2.1.

Workarounds:

None

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`web3-utils`	≥ 4.0.1&&< 4.2.1	4.2.1`npm install web3-utils@4.2.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for web3-utils, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update web3-utils to 4.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21505 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.

Frequently Asked Questions

### Impact: The mergeDeep() function in the web3-utils package has been identified for Prototype Pollution vulnerability. An attacker has the ability to modify an object's prototype, which could result in changing the behavior of all objects that inherit from the impacted prototype by providing carefully crafted input to function. ### Patches: It has been fixed in web3-utils version 4.2.1 so all packages and apps depending on web3-utils >=4.0.1 and <=4.2.0 should upgrade to web3-utils 4.2.1. ### Workarounds: None