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CRITICAL severity

CVE-2021-23448

CRITICAL

CVE-2021-23448 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in config-handler. 2 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2021-23448 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Prototype Pollution in config-handler

Also known asGHSA-2w3f-9w3q-qw77SNYK-JS-CONFIGHANDLER-1564947
Published
Oct 11, 2021
Updated
Jul 9, 2026
Affected
1 pkg
Patched
None yet
Exploits
2 known
Exploitation data as of Jul 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.

config-handlernpm
16downloads / week

Description

All versions of package config-handler are vulnerable to Prototype Pollution when loading config files.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
📦npmconfig-handlerall versionsNo fix
Exploits & PoCs
2

Research 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 dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for config-handler. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of config-handler has shipped for CVE-2021-23448 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    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.

  4. How O3 protects you

    O3 pinpoints whether CVE-2021-23448 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-23448. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

All versions of package config-handler are vulnerable to Prototype Pollution when loading config files.
O3 Security · Impact-Aware SCA

Is CVE-2021-23448 in your dependencies?

O3 detects CVE-2021-23448 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

CVE-2021-23448: Prototype Pollution in… | O3 Security