Microsoft · Internet Explorer

CVE-2021-27085

Internet Explorer Remote Code Execution Vulnerability

Exploited in attacks High 8.8 Attack chance: 5.4%

What it is

Internet Explorer Remote Code Execution Vulnerability

CISA: Microsoft Internet Explorer contains an unspecified vulnerability that allows for remote code execution.

What to do

Apply updates per vendor instructions.

Deadline for US federal agencies: November 17, 2021

msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27085

Added to the CISA list: November 3, 2021
Published: March 11, 2021
Severity: High 8.8 CVSS 3.1
Chance of attacks in the next 30 days (EPSS): 5.4% in the top 7.3% of all known vulnerabilities
More details: NVD · CVE.org · CISA

More exploited flaws from Microsoft

Added	Vulnerability	Product	Severity	Attack chance
May 20, 2026	Use-After-FreeCVE-2010-0249	Internet Explorer	High 8.8	92%
May 20, 2026	Use-After-FreeCVE-2010-0806	Internet Explorer	High 8.8	82%
Oct 6, 2025	Uninitialized Memory CorruptionCVE-2010-3962	Internet Explorer	High 8.1	97%
Aug 12, 2025	Resource Management ErrorsCVE-2013-3893	Internet Explorer	High 8.8	88%
Jul 23, 2024	Use-After-FreeCVE-2012-4792	Internet Explorer	High 8.8	79%
Mar 30, 2023	Memory CorruptionCVE-2013-3163	Internet Explorer	High 8.8	71%
Jun 8, 2022	Use-After-FreeCVE-2012-4969	Internet Explorer	High 8.1	80%
May 25, 2022	Information DisclosureCVE-2013-7331	Internet Explorer	Medium 6.5	50%

All of them →

Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.