CVE-2016-3298

CVE-2016-3298 is an information disclosure flaw (CWE-200) in the Microsoft Internet Messaging API used by Internet Explorer, in which the API improperly handles objects in memory. Exploitation requires driving Internet Explorer to process attacker-influenced content so the Messaging API mishandles memory, after which the attacker can probe whether specific files exist on the victim's disk. An attacker gains only limited reconnaissance value — confirming file presence for fingerprinting — rather than code execution or direct data theft. Only systems running Microsoft Internet Explorer, as cataloged by CISA, are affected; CISA added the bug to the Known Exploited Vulnerabilities catalog on 2022-05-24, confirming exploitation in the wild, though any ransomware association is unknown. EPSS estimates a 32.8% probability of exploitation within 30 days (98th percentile), no public proof-of-concept is known, and a CVSS score has not yet been published in this dataset.

What to do: Apply Microsoft's security update for CVE-2016-3298 per vendor instructions, as mandated by the CISA KEV catalog (added 2022-05-24, so remediation deadlines apply to federal agencies and many regulated environments). Audit any Windows hosts where Internet Explorer is still used for interactive browsing and confirm the patch is installed; because the flaw only permits probing for file existence, residual risk after patching is low.