Improper input validation in cups - CVE-2026-34990
Published: April 2, 2026 / Updated: April 17, 2026
cups
Detailed vulnerability description
The vulnerability allows a local user to execute arbitrary code with root privileges.
The vulnerability exists due to improper access control in CUPS when processing IPP requests for creating local printers. A local user can send a specially crafted IPP request to create a temporary printer with a file:// URI and then promote it to a shared printer, bypassing device restrictions and causing the system to write arbitrary files as root. This can lead to arbitrary code execution with root privileges.
The attacker must have the ability to send requests to localhost:631 and bind to a local port. The attack involves a race condition during printer validation, which may require multiple attempts to succeed.