CVE-2021-31955

MEDIUMNVD 5.59.0▲Trending — 5 sources updated this weekExploited in the wild

5.5

Windows Kernel Information Disclosure Vulnerability

CVSS v3: 5.5
EG Score: 9.0(high)
EPSS: 88.0%
KEV: ⚠ Exploited

Published

June 8, 2021

Last Modified

October 30, 2025

References (3)

secure@microsofthttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955
af854a3a-2127-422b-91ae-364da2661108https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955
134c704f-9b21-4f2e-91b3-4a467353bcc0https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955

Weakness Classification(2)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Microsoft MSRCCVE-2021-319552021-06-08
Windows Kernel Information Disclosure Vulnerability

Data Freshness Timeline

(refreshed 20× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-31 23:58 UTCEG score recompute▲ 3.50
2026-05-31 23:58 UTCVendor advisory
2026-05-31 23:58 UTCGHSA enrichment
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 22:20 UTCkev_newly_listed
2026-05-29 13:42 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 20:35 UTCkev_newly_listed
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 19:13 UTCkev_newly_listed
2026-05-26 15:19 UTCEG score recompute
2026-05-26 15:19 UTCVendor advisory
2026-05-26 15:19 UTCGHSA enrichment

Publicly available exploits

(2 references)

Working exploit code is in the public domain (2 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

GitHub PoCApexPredator-InfoSec/forti_shield
First seen Oct 29, 2025
A combined POC for CVE-2021-31955, CVE-2015-4077, and CVE-2015-5736
Open source ↗
GitHub PoCfreeide/CVE-2021-31955-POC
First seen Jun 26, 2021
Open source ↗

Frequently asked(6)

What is CVE-2021-31955?

CVE-2021-31955 is a medium vulnerability published on June 8, 2021. Windows Kernel Information Disclosure Vulnerability

When was CVE-2021-31955 disclosed?

CVE-2021-31955 was first published in the National Vulnerability Database on June 8, 2021, with the most recent update on October 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-31955 actively exploited?

Yes. CISA added CVE-2021-31955 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Microsoft Windows. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.

What is the CVSS score of CVE-2021-31955?

CVE-2021-31955 has a CVSS v3 base score of 5.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.

Which products are affected by CVE-2021-31955?

CVE-2021-31955 affects Microsoft Windows. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.

How do I remediate CVE-2021-31955?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-31955, 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-2021-31955

Explore →

Is Your Infrastructure Affected by CVE-2021-31955?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2021-31955

Published

Last Modified

References (3)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Publicly available exploits

Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-31955?

Same vendor

Same CWE

CVE-2021-31955

📅 Published

🔄 Last Modified

🔗 References (3)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Publicly available exploits

❓ Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-31955?

🔗 Related CVEs(same vendor + same CWE)

Same vendor

Same CWE

Published

Last Modified

References (3)

Frequently asked(6)

Related CVEs(same vendor + same CWE)