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CRITICAL severity

CVE-2020-28270 — object-hierarchy-access

CRITICALFix: mjpclab/object-hierarchy-access@7b1aa13

CVE-2020-28270 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in object-hierarchy-access. 1 public exploit reference exists, so weaponization risk is real. A fix is available for object-hierarchy-access — see the affected versions and patch details below.

Prototype pollution in object-hierarchy-access

Also known asGHSA-fxwf-45c7-4ppr
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
3.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs90th percentile — riskier than 90% of all scored CVEsHighest risk
2.45%3.08%3.71%4.35%2.9%3.8%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2020-28270 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.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
object-hierarchy-accessnpm
86downloads / week

Description

Prototype pollution vulnerability in 'object-hierarchy-access' versions 0.2.0 through 0.32.0 allows attacker to cause a denial of service and may lead to remote code execution.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmobject-hierarchy-access≥ 0.2.0&&< 0.33.00.33.0npm install object-hierarchy-access@0.33.0

Affected Products

1 product · 1 configurations
Application
object-hierarchy-accessmjpclab
≥ 0.2.0 && ≤ 0.32.0
range
Exploits & PoCs
1

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

Prototype pollution vulnerability in 'object-hierarchy-access' versions …

whitesourcesoftware.comNVDJul 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update object-hierarchy-access to 0.33.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-28270 is resolved across your whole dependency graph.

  3. 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.

Frequently Asked Questions

Prototype pollution vulnerability in 'object-hierarchy-access' versions 0.2.0 through 0.32.0 allows attacker to cause a denial of service and may lead to remote code execution.
O3 Security · Impact-Aware SCA

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CVE-2020-28270: object-hierarchy RCE — Fixed in 0.33.0