CVE-2015-2419

CVE-2015-2419 is a memory corruption flaw (CWE-119) in the JScript engine used by Microsoft Internet Explorer, allowing remote attackers to execute arbitrary code or cause a denial of service through a crafted website. It is triggered when a user visits an attacker-controlled page whose JScript content corrupts memory in the affected browser process. A successful attacker gains remote code execution in the context of the logged-on user (or crashes the browser), which makes drive-by and exploit-kit delivery routes viable. Any Windows user running the affected versions of Internet Explorer at the time of disclosure was exposed, and Microsoft shipped fixes as part of its July 2015 security updates. The flaw is listed in CISA's Known Exploited Vulnerabilities catalog (added 2022-03-28), carries a 53.4% EPSS (99th percentile), and related reporting places it among the top vulnerabilities used by exploit kits in 2015-2016.

What to do: Apply Microsoft's July 2015 security updates for Internet Explorer per vendor instructions, as required by the CISA KEV catalog, and verify that any legacy Windows systems still running Internet Explorer have received them. Because exploitation typically occurs via drive-by web attacks, retire or fully patch IE on client endpoints and keep endpoint protection enabled to catch exploit-kit delivery. Confirm no workstations remain on unpatched IE builds, since this entry has been in CISA KEV since March 2022 and exploitation probability remains high (EPSS 53.4%).