CVE-2021-3918

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 3.6%, top 12% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 4%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

json-schema is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation4% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
88.1%
KEV
Not listed

Published

November 13, 2021

Last Modified

January 17, 2025

Advisory Details (4)

Auto-updated May 26, 2026
Patch available. Sources: github_commit.
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20250117-0004/
generic Patch Available

[SECURITY] [DLA 3228-1] node-json-schema security update

https://lists.debian.org/debian-lts-announce/2022/12/msg00013.html
generic

huntr - The world’s first bug bounty platform for AI/ML

https://huntr.dev/bounties/bb6ccd63-f505-4e3a-b55f-cd2662c261a9
github_commit

commit 22f146111f54 (kriszyp/json-schema)

Fix landed in kriszyp/json-schema commit 22f146111f54 — awaiting tagged release

https://github.com/kriszyp/json-schema/commit/22f146111f541d9737e832823699ad3528ca7741

Vendor Advisories for CVE-2021-3918(5)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(11)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntunode-json-schema (0.2.3-1+deb10u1build0.18.04.1) @ bionic2026-05-26ubuntu
redhatnodejs:12-8040020220523155137.522a0ee42022-07-19redhat
redhatnodejs:12-8020020220523154454.4cda2c842022-06-28redhat
redhatnodejs:12-8060020220523160029.ad008a3a2022-06-21redhat
redhatrhacm2/search-api-rhel8:v2.5.0-252022-06-09redhat
redhatnodejs:12-8010020220518102644.c27ad7f82022-06-07redhat
redhatrh-nodejs12-nodejs-0:12.22.12-2.el72022-06-06redhat
redhatnodejs:14-8050020211213115342.c53685002022-02-01redhat
redhatnodejs:14-8040020211213111158.522a0ee42022-01-25redhat
redhatrh-nodejs14-nodejs-nodemon-0:2.0.3-6.el72022-01-06redhat
redhatnodejs:16-8050020211206113934.c53685002021-12-16redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
json-schema—0.4.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(8)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 13× in last 7d / 50× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 104 total refreshes for this CVE.

  1. 2026-07-23 02:03 UTCEG score recompute
  2. 2026-07-22 22:50 UTCEG score recompute
  3. 2026-07-22 14:06 UTCEPSS rescore
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  74. 2026-05-26 07:35 UTCEG score recompute
  75. 2026-05-26 07:35 UTCVendor advisory

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-3918?
CVE-2021-3918 is a critical vulnerability published on November 13, 2021. json-schema is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
When was CVE-2021-3918 disclosed?
CVE-2021-3918 was first published in the National Vulnerability Database on November 13, 2021, with the most recent update on January 17, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3918 actively exploited?
CVE-2021-3918 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 88.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3918?
CVE-2021-3918 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-3918?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3918, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-3918

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