# CVE-2021-26411

Internet Explorer Memory Corruption Vulnerability

- Page: https://www.vulneraibility.com/cve/CVE-2021-26411
- CVSS: 8.8
- Known exploited: yes, in CISA KEV since 2021-11-03; CISA due date 2021-11-17; known ransomware use
- EPSS: 81.67% (percentile 99.6)
- Unvetted proof-of-concept code on GitHub: 1 GitHub proof of concept (first 2021-11-22)
- CISA SSVC: exploitation active, automatable no, technical impact partial (assessed 2026-08-12)
- Weakness: CWE-416
- Published: 2021-03-11

## Affected versions

- Microsoft Internet Explorer 11: affected >= 1.0.0 and < 10.0.17134.2087
- Microsoft Internet Explorer 9: affected >= 1.0.0 and < 6.0.6003.21070
- Microsoft Microsoft Edge (EdgeHTML-based): affected >= 1.0..0 and < 10.0.17134.2087

A version outside these ranges is not a statement that it is unaffected.

## References

- [patch] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26411
- [other] https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26411
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26411

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.