A security researcher has released an exploit targeting a Windows vulnerability disclosed in 2020, warning that it might have never been patched.
The flaw, tracked as CVE-2020-17103 (CVSS score of 7.0), is described as a privilege escalation issue in the Windows Cloud Filter driver.
Google Project Zero’s researchers reported the weakness in 2020, and Microsoft rolled out fixes for it as part of its December 2020 Patch Tuesday updates.
Per Project Zero’s report on CVE-2020-17103, the vulnerable Windows Cloud Filter driver allows registry key manipulation via an undocumented API.
An attacker could use an unauthenticated network session to create a key in the DEFAULT user hive without access checks, enabling privilege escalation and potentially leading to system code execution, the report reads.
Now, a cybersecurity researcher known as Chaotic Eclipse and Nightmare Eclipse has released MiniPlasma, an exploit that targets the security defect to spawn a System shell.
The researcher says the original proof-of-concept (PoC) code released by Project Zero researchers works without changes, noting that either the vulnerability was never resolved or the patches were rolled back.
“After investigating, it turns out the exact same issue that was reported to Microsoft by Google Project Zero is actually still present, unpatched,” Chaotic Eclipse says.
Chaotic Eclipse recently dropped exploits for several unpatched vulnerabilities in Microsoft products, such as BlueHammer, YellowKey, and GreenPlasma, saying they are displeased with how the tech giant handles vulnerability reports.
According to Tharros Labs senior principal vulnerability analyst Will Dormann, MiniPlasma works on Windows 11 systems with the May 2026 security updates installed.
“I’ll note that it does not seem to work on the latest Insider Preview Canary Windows 11,” Dormann says.
“Microsoft is investigating this report and will take appropriate action to protect customers as soon as possible,” a Microsoft spokesperson said, responding to a SecurityWeek inquiry.
*Updated with statement from Microsoft.
Related: Microsoft Warns of Exchange Server Zero-Day Exploited in the Wild
Related: Microsoft Patches Critical Zero-Click Outlook Vulnerability Threatening Enterprises
Related: No Patch for New PhantomRPC Privilege Escalation Technique in Windows
Related: Incomplete Windows Patch Opens Door to Zero-Click Attacks
