Microsoft Office Remote Code Execution (CVE-2009-0238)
Severity: high · Patch status: unknown · Since 2026-04-14 · CVE-2009-0238
Microsoft Office Excel contains a remote code execution vulnerability that could allow an attacker to take complete control of an affected system if a user opens a specially crafted Excel file that includes a malformed object. CISA added CVE-2009-0238 to its Known Exploited Vulnerabilities catalog on Apr 14, 2026, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- US federal agencies must remediate by Apr 28, 2026 (BOD 22-01); treat that as the outer limit.
Sources
All live incidents on Threat Watch
