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CVE-2021-26411

Internet Explorer Memory Corruption Vulnerability

HIGH
8.8
CVSS Score
Published: March 11, 2021 at 03:07 PM UTC
Updated: October 1, 2026 at 09:17 PM UTC
17 products affected across 1 vendorInternet ExplorerEdgeWindows Server 2016

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Severity
HIGH8.8
Exploitation
CISA KEV
Exploit prediction
EPSS 82%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score81.7%

EPSS (Exploit Prediction Scoring System) estimates a 81.7% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

Microsoft Internet Explorer contains an unspecified vulnerability that allows for memory corruption.

Required Action
Apply updates per vendor instructions.
Ransomware Use
Known
Added to KEV
Nov 3, 2021
Remediation Due
Nov 17, 2021
1810 days overdue
Notes
https://nvd.nist.gov/vuln/detail/CVE-2021-26411

Description

Internet Explorer Memory Corruption Vulnerability

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Edge· Microsoft
95%
1.0..0 ≤ v < 10.0.17134.20871.0..0
Affected range stops below 10.0.17134.2087, so it looks safe — our inference, not a vendor statement
microsoft-windows-10-1507 (environment) · microsoft-windows-10-1607 (environment) · microsoft-windows-10-1803 (environment) · microsoft-windows-10-1809 (environment) · microsoft-windows-10-1903 (environment) · microsoft-windows-10-1909 (environment) · microsoft-windows-10-2004 (environment) · microsoft-windows-10-20h2 (environment) · microsoft-windows-server-2016 (environment) · microsoft-windows-server-2019 (environment)
Internet Explorer· Microsoft
95%
1.0.0 ≤ v < 10.0.17134.20871.0.0 ≤ v < 6.0.6003.210701.0.0119
Affected range stops below 10.0.17134.2087, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.0.6003.21070, so it looks safe — our inference, not a vendor statement
microsoft-windows-10-1507 (environment) · microsoft-windows-10-1607 (environment) · microsoft-windows-10-1803 (environment) · microsoft-windows-10-1809 (environment) · microsoft-windows-10-1903 (environment) · microsoft-windows-10-1909 (environment) · microsoft-windows-10-2004 (environment) · microsoft-windows-10-20h2 (environment) · microsoft-windows-7 (environment) · microsoft-windows-8-1 (environment) · microsoft-windows-rt-8-1 (environment) · microsoft-windows-server-2008 (environment) · microsoft-windows-server-2012 (environment) · microsoft-windows-server-2016 (environment) · microsoft-windows-server-2019 (environment)
Windows 10 1507· Microsoftdevice
80%
All versions
Windows 10 1607· Microsoftdevice
80%
All versions
Windows 10 1803· Microsoftdevice
80%
All versions
Windows 10 1809· Microsoftdevice
80%
All versions
Windows 10 1903· Microsoftdevice
80%
All versions
Windows 10 1909· Microsoftdevice
80%
All versions
Windows 10 2004· Microsoftdevice
80%
All versions
Windows 10 20H2· Microsoftdevice
80%
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

PatchVendor Advisory
Source: [email protected]
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26411
US Government Resource
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26411
Vendor AdvisoryPatch
Source: cverecord
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26411

SSVC — Action Prioritization

SSVCActiveNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHmicrosoft
Vector?

Quick Info

StatusANALYZED
CWE
CWE-416

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