How severe is CVE-2021-26411?

CVE-2021-26411 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability low.

Is CVE-2021-26411 being actively exploited?

Yes. CVE-2021-26411 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-26411?

CVE-2021-26411 primarily affects Microsoft Edge. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26411?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-26411 have an EU (EUVD) identifier?

Yes. CVE-2021-26411 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-13217. It is also flagged as exploited in the EUVD (since 2021-11-03).

When was CVE-2021-26411 published?

CVE-2021-26411 was published on 2021-03-11 and last updated on 2026-08-19.

CVE-2021-26411

CVE-2021-26411 is a high-severity vulnerability in Microsoft Edge with a CVSS 3.x base score of 8.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-416.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 5.1
EPSS exploit prediction: 81% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2021-11-03)
EU (EUVD) id: EUVD-2021-13217
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2021-11-03)
Weakness: CWE-416
Affected product: Microsoft Edge
Published: 2021-03-11
Last modified: 2026-08-19

Description

Internet Explorer Memory Corruption Vulnerability

Frequently asked questions

What is CVE-2021-26411?: Internet Explorer Memory Corruption Vulnerability
How severe is CVE-2021-26411?: CVE-2021-26411 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability low.
Is CVE-2021-26411 being actively exploited?: Yes. CVE-2021-26411 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-26411?: CVE-2021-26411 primarily affects Microsoft Edge. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26411?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-26411 have an EU (EUVD) identifier?: Yes. CVE-2021-26411 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-13217. It is also flagged as exploited in the EUVD (since 2021-11-03).
When was CVE-2021-26411 published?: CVE-2021-26411 was published on 2021-03-11 and last updated on 2026-08-19.

References

Affected products (3)

cpe:2.3:a:microsoft:edge:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:internet_explorer:11:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:internet_explorer:9:*:*:*:*:*:*:*

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