CVE-2026-55480: openprinting cups Link Following

Vulnerability summary

CVE-2026-55480 is a medium (CVSS 5.7) Link Following vulnerability in openprinting cups. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 4.3% of scored vulnerabilities.

Timeline

1. 15-10-2026
   PublishedVulnerability first disclosed.

Description

OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. Prior to 2.4.20, copy_model() in scheduler/ipp.c creates a predictable TempDir/<connection-number>.ppd path in an lp-group-writable directory and opens it as root without O_EXCL or O_NOFOLLOW. Exploitation requires an lp-group process able to write that directory to predict the connection-derived name and plant a symlink before the root open, while a privileged add-printer or modify-printer operation using a model PPD triggers copy_model(). The reporter treats an existing lp foothold and the privileged operation as distinct prerequisites, while the maintainer assesses high privileges because installing the relevant filter or administering the printer requires root or print-administrator access. If the race succeeds, the root scheduler follows the symlink and truncates or overwrites a root-writable target with generated PPD data, compromising file integrity or availability. This issue is fixed in version 2.4.20.

• CWE-59Improper Link Resolution Before File Access ('Link Following')The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
• CWE-377Insecure Temporary FileCreating and using insecure temporary files can leave application and system data vulnerable to attack.