CVE-2021-26411VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-26411: Microsoft Internet Explorer Memory Corruption Vulnerability

Affects Microsoft Internet ExplorerSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 11/17/2021
Ransomware: Used in ransomware campaigns
EPSS: 81.7% chance of exploitation in 30 days – higher than 99% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-26411 (opens in a new tab)

Description

CVE-2021-26411 is a high-severity memory corruption vulnerability in Microsoft Internet Explorer. The flaw allows for memory corruption, which can be exploited by attackers. This vulnerability has been exploited in the wild and is known to have been used in ransomware campaigns. No specific affected versions or patch information is provided in the available data.

Summary

Microsoft Internet Explorer contains an unspecified memory corruption vulnerability identified as CVE-2021-26411. The vulnerability allows attackers to corrupt memory, potentially leading to arbitrary code execution or other impacts. It has been observed in active exploitation scenarios, including ransomware campaigns. The exact technical details and affected versions are not specified in the provided information.

Impact

The vulnerability enables memory corruption in Internet Explorer, which attackers have exploited in the wild. This exploitation has been linked to ransomware campaigns, indicating a significant risk of system compromise and data loss. The high severity rating reflects the potential for serious impact on affected systems.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users should monitor Microsoft's security advisories for updates. Until a fix is available, consider limiting or disabling the use of Internet Explorer to reduce exposure.

Weaknesses

CWE-416Use After Free (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:12:03 UTC

Weaknesses

References

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