Skip to content
brandefense.io
Request A Demo
Vulnerability Intelligence

CVE-2026-21513

HighExploitedPublic exploit

MSHTML Framework Security Feature Bypass Vulnerability

Published Feb 10, 2026 · Updated Aug 19, 2026

Key Facts

Patch immediately
  • CVE-2026-21513 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Windows 10 1607 (Microsoft), Windows 10 1809 (Microsoft), windows 10 21H2 (Microsoft) and 22 more products.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 10, 2026. Public exploit code is available.
  • EPSS estimates a 16% probability of exploitation in the next 30 days.
  • Fixed versions are available, including Windows 10 1607 10.0.14393.8868, Windows 10 1809 10.0.17763.8389, windows 10 21H2 10.0.19044.6937.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

8.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

16%

Higher than 96.8% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2026-21513 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVFeb 10, 2026Mar 3, 2026Not reported
Industry KEV feedFeb 10, 2026Mar 3, 2026Not reported
CIRCL KEVFeb 10, 2026Mar 3, 2026Not reported
ENISA EUVDFeb 10, 2026n/aNot reported

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Affected Products

84 affected entries in total
ProductAffected versionsFixed in
Windows 10 1607Microsoft10.0.14393.886810.0.14393.8868
Windows 10 1809Microsoft10.0.17763.838910.0.17763.8389
windows 10 21H2Microsoft10.0.19044.693710.0.19044.6937
windows 10 22H2Microsoft10.0.19045.693710.0.19045.6937
windows 11 23H2Microsoft10.0.22631.664910.0.22631.6649
20 more affected products in the full CVE brief

Patched Releases

Windows 10 1607

10.0.14393.8868

Windows 10 1809

10.0.17763.8389

windows 10 21H2

10.0.19044.6937

windows 10 22H2

10.0.19045.6937

windows 11 23H2

10.0.22631.6649

windows 11 24H2

10.0.26100.7781, 10.0.26100.7840

windows 11 25H2

10.0.26200.7781, 10.0.26200.7840

windows 11 26H1

10.0.28000.1575

Windows Server 2012

6.2.9200.25923

windows server 2012 R2

6.3.9600.23022

Windows Server 2016

10.0.14393.8868

Windows Server 2019

10.0.17763.8389

Windows Server 2022

10.0.20348.4711, 10.0.20348.4773

Windows Server 2022 23h2

10.0.25398.2149

Windows Server 2025

10.0.26100.32313, 10.0.26100.32370

Windows Server 23h2

10.0.25398.2149

Windows 10 Version 1607

10.0.14393.8868

Windows 10 Version 1809

10.0.17763.8389

Windows 10 Version 21H2

10.0.19044.6937

Windows 10 Version 22H2

10.0.19045.6937

Windows 11 version 22H3

10.0.22631.6649

Windows 11 Version 23H2

10.0.22631.6649

Windows 11 Version 24H2

10.0.26100.7840

Windows 11 Version 25H2

10.0.26200.7840

Windows 11 version 26H1

10.0.28000.1575

Timeline

  1. Publicly disclosed

    Feb 10, 2026

  2. Added to CISA KEV

    Feb 10, 2026

  3. Added to Industry KEV feed

    Feb 10, 2026

  4. Added to CIRCL KEV

    Feb 10, 2026

  5. Added to ENISA EUVD

    Feb 10, 2026

  6. Last updated

    Aug 19, 2026

Weakness Type

  • CWE-693 Protection Mechanism Failure

References

7 more references in the full CVE brief

FAQ

Common Questions.

Is CVE-2026-21513 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.

Request A Demo