cve-2026-34990-POC
Description
Technical analysis and proof-of-concept research for CVE-2026-34990, a local privilege-escalation vulnerability affecting CUPS. This repository documents the vulnerability mechanics, CUPS/IPP request flow, authentication-token disclosure, the localhost callback technique, and the subsequent privilege-escalation primitive.
CVE-CVE-2026-34990 Details
OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, a local unprivileged user can coerce cupsd into authenticating to an attacker-controlled localhost IPP service with a reusable Authorization: Local ... token. That token is enough to drive /admin/ requests on localhost, and the attacker can combine CUPS-Create-Local-Printer with printer-is-shared=true to persist a file:///... queue even though the normal FileDevice p...