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CVE-2021-26411

Microsoft Internet Explorer Memory Corruption

8.8 HIGHActively exploited (CISA KEV)Used in ransomwareEPSS 80.8%
  1. Published11 Mar 2021
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due17 Nov 2021
Actively exploited (CISA KEV)

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

Added to KEV: 3 Nov 2021Federal remediation due: 17 Nov 2021Used in ransomware

Description

Internet Explorer Memory Corruption Vulnerability

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeChanged
ConfidentialityLow
IntegrityHigh
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L

Affected products

Microsoft Edgeall versions
Microsoft Internet Explorer11 · 9

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2021-26411 being actively exploited?

Yes. CVE-2021-26411 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.

How severe is CVE-2021-26411?

CVE-2021-26411 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 80.8% probability of exploitation.

Which products are affected by CVE-2021-26411?

Affected products include Microsoft Edge, Microsoft Internet Explorer.

How do I fix CVE-2021-26411?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-26411 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.