CVE-2021-26411

CVE-2021-26411 is a high-severity (CVSS 8.8) vulnerability in Microsoft Internet Explorer. CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by November 17, 2021. CISA also lists it as known to be used in ransomware campaigns, so it should be prioritised accordingly. Microsoft has 390 vulnerabilities in the KEV catalog, 117 of them linked to ransomware.

Internet Explorer Memory Corruption Vulnerability

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

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