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CRITICAL severity

CVE-2021-23373 — set-deep-prop

CRITICAL

CVE-2021-23373 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in set-deep-prop. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

set-deep-prop Prototype Pollution

Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
1 known
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs68th percentile — riskier than 68% of all scored CVEsHighest risk
0.00%0.56%1.12%1.69%0.4%1.2%May 26Sep 26Nov 26

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.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
set-deep-propnpm
37downloads / week

Description

All versions of package set-deep-prop are vulnerable to Prototype Pollution via the main functionality.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
📦npmset-deep-propall versionsNo fix

Affected Products

1 product · 1 configurations
Application
set-deep-propset-deep-prop_project
all
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.

Detection & mitigation playbook

Open-source dependency
  1. Detect

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

  2. Remediation status

    The records we use list no patched version of set-deep-prop for CVE-2021-23373. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  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.

Frequently Asked Questions

All versions of package set-deep-prop are vulnerable to Prototype Pollution via the main functionality.
O3 Security · Impact-Aware SCA

Is CVE-2021-23373 in your dependencies?

Find it across npm, including transitive dependencies.

CVE-2021-23373: set-deep-prop (Critical 9.8)