Is CVE-2021-26411 in the CISA KEV catalog?

Yes. CVE-2021-26411 is on the CISA Known Exploited Vulnerabilities list, added 2021-11-03, and has known ransomware campaign use.

What is the CVSS severity of CVE-2021-26411?

CVE-2021-26411 has a CVSS v3 base score of 8.8 (HIGH).

What is the EPSS score for CVE-2021-26411?

CVE-2021-26411 has an EPSS score of 81.10% (100th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2021-26411

HIGHCISA KEVEPSS 100th pctl

8.8

CVSS v3

NVD

Description

Internet Explorer Memory Corruption Vulnerability

CWE-416Use After Free

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeChanged

Impact

ConfidentialityLow

IntegrityHigh

AvailabilityLow

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

Exploit Intelligence

81.10%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Microsoft Internet Explorer Memory Corruption Vulnerability

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

Apply updates per vendor instructions.

Remediation due: 2021-11-17

Associated with ransomware campaigns

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-30.