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CRITICAL severity

CVE-2020-28278 shvl

CRITICAL

CVE-2020-28278 is a critical-severity (CVSS 9.8) remote code execution vulnerability in shvl. 1 public exploit reference exists, so weaponization risk is real. A fix is available for shvl — see the affected versions and patch details below.

shvl vulnerable to prototype pollution

Also known asGHSA-pqwc-3vhw-qcvq
Published
Dec 29, 2020
Updated
Jul 9, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs87th percentile — riskier than 87% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2020-28278 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

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.

27other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
shvlnpm
141Kdownloads / week

Description

Prototype pollution vulnerability in 'shvl' versions 1.0.0 through 2.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmshvl1.0.0&&< 2.0.22.0.2npm install shvl@2.0.2
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 shvl, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update shvl to 2.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-28278 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-28278 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2020-28278. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Prototype pollution vulnerability in 'shvl' versions 1.0.0 through 2.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.
O3 Security · Impact-Aware SCA

Is CVE-2020-28278 in your dependencies?

O3 Security finds CVE-2020-28278 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2020-28278: shvl RCE (Critical 9.8) | O3 Security