CVE-2026-55480

NameCVE-2026-55480
DescriptionOpenPrinting 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1150561

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
cups (PTS)bookworm, bookworm (security)2.4.2-3+deb12u9vulnerable
trixie2.4.10-3+deb13u2vulnerable
trixie (security)2.4.10-3+deb13u1vulnerable
forky2.4.18-1vulnerable
sid2.4.20-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
cupssource(unstable)2.4.20-11150561

Notes

https://github.com/OpenPrinting/cups/security/advisories/GHSA-jj94-x3qh-ffp9
Fixed by: https://github.com/OpenPrinting/cups/commit/98adfd855950e806508f961d5438ad32e26aac62 (v2.4.20)

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