The PoC-code for this vulnerability was being made publicly available by mistake before official patch release. The vulnerability is considered a zero-day.
Vulnerable component: Windows Server
CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C
CWE-ID: CWE-94 - Improper Control of Generation of Code ('Code Injection')
The vulnerability allows a remote user to execute arbitrary code on the target system.
The vulnerability exists due to improper input validation within the RpcAddPrinterDriverEx() function. A remote user can send a specially crafted request to the Windows Print Spooler and execute arbitrary code with SYSTEM privileges.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Note, the vulnerability is being considered a zero-day and dubbed PrintNightmare. This is a different vulnerability than #VU54508 (CVE-2021-1675).