Code Injection in Windows and Windows Server - CVE-2021-34527
Published: June 8, 2021 / Updated: September 6, 2022
Vulnerability identifier: #VU53886
CSH Severity: Critical
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red
CVE-ID: CVE-2021-34527
CWE-ID: CWE-94
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vendor: Microsoft
Affected software:
Windows
Windows Server
Windows
Windows Server
Detailed vulnerability description
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).
How to mitigate CVE-2021-34527
Install update from vendor's website.