How severe is CVE-2020-35149?

CVE-2020-35149 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-35149?

CVE-2020-35149 affects the following packages: mquery (npm). Ecosystems affected: npm.

How do I fix CVE-2020-35149?

Update mquery to 3.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-35149 is resolved across your whole dependency graph.

How do I detect CVE-2020-35149 in my npm dependencies?

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

How do I mitigate CVE-2020-35149 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-2020-35149 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-35149 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-2020-35149?

CVE-2020-35149 has an EPSS (Exploit Prediction Scoring System) score of 1.0%, placing it in the 63th 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.

When was CVE-2020-35149 published, and has it been updated?

CVE-2020-35149 was published on December 11, 2020 and was last updated on August 27, 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

MEDIUM severity

CVE-2020-35149 — mquery

MEDIUMFix: aheckmann/mquery@792e69f

CVE-2020-35149 is a medium-severity (CVSS 5.3) vulnerability in mquery. A fix is available for mquery — see the affected versions and patch details below.

Code Injection in mquery

Also known asGHSA-45q2-34rf-mr94

Published

Dec 11, 2020

Updated

Aug 27, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.0%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2020-35149 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 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.

88other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

mquerynpm

6.1Mdownloads / week

Description

lib/utils.js in mquery before 3.2.3 allows a pollution attack because a special property (e.g., proto) can be copied during a merge or clone operation.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`mquery`	all versions	3.2.3`npm install mquery@3.2.3`

Affected Products

1 product · 1 configurations

Application

mquerymquery_project

< 3.2.3

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mquery, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mquery to 3.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-35149 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.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

The affected version of mquery is a dependency of the mongoose library. The exploitation of this vulnerability requires authenticated access, consequently, the CVSSv3 score for RHACM is lower than the score of the flaw.

Product	Fixed in	Advisory
Red Hat Advanced Cluster Management for Kubernetes 2.1 for RHEL 8	`rhacm2/acm-must-gather-rhel8:v2.1.6-6`	RHSA-2021:1369

Frequently Asked Questions

lib/utils.js in mquery before 3.2.3 allows a pollution attack because a special property (e.g., __proto__) can be copied during a merge or clone operation.

O3 Security · Impact-Aware SCA

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