CVE-2021-40449

HIGHNVD 7.89.0▲Trending — 5 sources updated this weekExploited in the wild

7.8

Win32k Elevation of Privilege Vulnerability

CVSS v3: 7.8
EG Score: 9.0(high)
EPSS: 99.7%
KEV: ⚠ Exploited

Published

October 13, 2021

Last Modified

October 30, 2025

Advisory Details (3)

Auto-updated Jun 3, 2026

⚠️ Active exploitation confirmed. Patch available. Sources: microsoft, cisa.

cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40449

microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449

generic

Packet Storm

http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html

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-2021-404492021-10-12
Win32k Elevation of Privilege 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.

2026-06-06 15:12 UTCEG score recompute
2026-06-06 15:12 UTCVendor advisory
2026-06-06 15:12 UTCGHSA enrichment
2026-06-06 13:46 UTCepss_batch
2026-06-06 13:46 UTCepss_batch
2026-06-06 11:06 UTCEG score recompute
2026-06-06 11:06 UTCVendor advisory
2026-06-06 11:06 UTCGHSA enrichment
2026-06-06 07:01 UTCEG score recompute
2026-06-06 07:01 UTCVendor advisory
2026-06-06 07:01 UTCGHSA enrichment
2026-06-06 02:55 UTCEG score recompute
2026-06-06 02:55 UTCVendor advisory
2026-06-06 02:55 UTCGHSA enrichment
2026-06-05 22:50 UTCEG score recompute
2026-06-05 22:50 UTCVendor advisory
2026-06-05 22:49 UTCGHSA enrichment
2026-06-05 22:45 UTCepss_batch
2026-06-05 22:43 UTCkev_newly_listed
2026-06-05 18:44 UTCEG score recompute

Publicly available exploits

(5 references)

Working exploit code is in the public domain (1 Metasploit module) (4 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

GitHub PoCKristal-g/CVE-2021-40449_poc
First seen Nov 7, 2021
Exploit for CVE-2021-40449
Open source ↗
GitHub PoChakivvi/CVE-2021-40449
First seen Oct 25, 2021
LPE exploit for a UAF in Windows (CVE-2021-40449).
Open source ↗
GitHub PoCKaLendsi/CVE-2021-40449-Exploit
First seen Oct 20, 2021
windows 10 14393 LPE
Open source ↗
GitHub PoCly4k/CallbackHell
First seen Oct 16, 2021
Exploit for CVE-2021-40449 - Win32k Elevation of Privilege Vulnerability (LPE)
Open source ↗
Metasploitexploit/windows/local/cve_2021_40449✓ verified
First seen Oct 12, 2021
Win32k NtGdiResetDC Use After Free Local Privilege Elevation
Open source ↗

Frequently asked(6)

What is CVE-2021-40449?

CVE-2021-40449 is a high vulnerability published on October 13, 2021. Win32k Elevation of Privilege Vulnerability

When was CVE-2021-40449 disclosed?

CVE-2021-40449 was first published in the National Vulnerability Database on October 13, 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-2021-40449 actively exploited?

Yes. CISA added CVE-2021-40449 to the Known Exploited Vulnerabilities catalog on November 17, 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-2021-40449?

CVE-2021-40449 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.

Which products are affected by CVE-2021-40449?

CVE-2021-40449 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-2021-40449?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40449, 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-2021-40449

Explore →

Is Your Infrastructure Affected by CVE-2021-40449?

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CVE-2021-40449

Published

Last Modified

Advisory Details (3)

Known Exploited Vulnerabilities Catalog | CISA

Security Update Guide - Microsoft Security Response Center

Packet Storm

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Publicly available exploits

Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-40449?

Same vendor

Same CWE

CVE-2021-40449

📅 Published

🔄 Last Modified

📋 Advisory Details (3)

Known Exploited Vulnerabilities Catalog | CISA

Security Update Guide - Microsoft Security Response Center

Packet Storm

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Publicly available exploits

❓ Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-40449?

🔗 Related CVEs(same vendor + same CWE)

Same vendor

Same CWE

Published

Last Modified

Advisory Details (3)

Frequently asked(6)

Related CVEs(same vendor + same CWE)