CVE-2013-3893

CVE-2013-3893 is a resource-management (memory corruption) flaw in Microsoft Internet Explorer that can allow remote code execution (CWE-399). It is triggered remotely, typically when a user views attacker-controlled web content in a vulnerable version of Internet Explorer. A successful attacker gains the ability to execute arbitrary code in the context of the current user, potentially compromising the workstation. Organizations still running Internet Explorer, which CISA notes may be end-of-life (EoL) and/or end-of-service (EoS), are affected; specific affected version ranges were not provided in the source data. The flaw was patched in Microsoft's October 2013 Patch Tuesday after being exploited in the wild (Operation DeputyDog, per related reporting), and CISA added it to the Known Exploited Vulnerabilities catalog on 2025-08-12 with a very high EPSS of 85.9% (100th percentile), indicating active or imminent exploitation.

What to do: Apply mitigations per Microsoft's vendor instructions and follow applicable BOD 22-01 guidance for cloud services, or discontinue use of Internet Explorer if mitigations are unavailable, per CISA's required action. Verify that affected systems have the October 2013 Patch Tuesday (or later) cumulative Internet Explorer security updates installed, and audit your estate for remaining legacy IE usage. Where IE is still needed for legacy sites, migrate to Microsoft Edge with IE mode and treat in-the-wild exploitation as likely given the KEV listing and 85.9% EPSS.