CVE-2022-41128

CVE-2022-41128 is a remote code execution flaw in the JScript9 scripting language on Microsoft Windows, classed by the CWE taxonomy as an out-of-bounds write (CWE-787), meaning crafted input can write past the end of an allocated memory buffer. Microsoft's description is limited, but flaws of this type in scripting engines are typically triggered when the engine processes attacker-crafted script content, such as script embedded in a web page or document. Successful exploitation would let an attacker execute arbitrary code in the context of the affected process on the target Windows system. Any Windows deployment that processes content through the JScript9 engine is affected, which spans a broad share of the Windows installed base. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2022-11-08, indicating confirmed in-the-wild exploitation; no public proof-of-concept is known, EPSS puts the 30-day exploitation probability at 24.6% (98th percentile), and ransomware use is unknown.

What to do: Apply Microsoft's Windows security updates per vendor instructions without delay, prioritizing internet-facing and user-workstation systems because the flaw is KEV-listed as actively exploited. Until patched, limit exposure to untrusted script-bearing web content and documents from unverified sources, and verify remediation status against Microsoft's update guidance.