CVE-2017-0199

CVE-2017-0199 is a remote code execution vulnerability in Microsoft Office and WordPad that stems from improper parsing of specially crafted files. Attackers trigger it by getting a user to open a malicious document, after which attacker-controlled code executes with the privileges of the logged-in user. Anyone running the affected Microsoft Office or WordPad software is exposed, and CISA notes the flaw has been leveraged in ransomware campaigns; no CVSS score is available in the source data. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2021-11-03, and EPSS assigns a 99.9% probability of exploitation within 30 days (100th percentile), indicating active, ongoing exploitation.

What to do: Apply Microsoft's security updates for Office and Windows per vendor instructions, as required by CISA's KEV catalog; the flaw was publicly reported as fixed in Microsoft's April 2017 security updates. Until patched, treat unsolicited Office documents and email attachments as high-risk, since exploitation requires a user to open a crafted file. Verify that all Office and WordPad installations across the estate—especially endpoints that handle untrusted documents—have received the update.