CVE-2026-55480
CUPS copy_model() creates a predictable PPD tempfile without O_EXCL/O_NOFOLLOW (symlink TOCTOU, lp → root)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.20 % · percentile 10 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
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.
Weaknesses (CWE)
References
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-jj94-x3qh-ffp9
- https://github.com/OpenPrinting/cups/commit/98adfd855950e806508f961d5438ad32e26aac62
- https://github.com/OpenPrinting/cups/commit/f6a11dae0f0f3b748fbca931e237be03ffe8e48e
- https://github.com/OpenPrinting/cups/releases/tag/v2.4.20
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.7 | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H | GitHub_M |
| CVSS 3.1 | MEDIUM 5.7 | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H | NVD · security-advisories@github.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-102205
- GCVE · GCVE-0-2026-55480
Affected configurations (NVD CPE)
cpe:2.3:a:openprinting:cups:*:*:*:*:*:*:*:*< 2.4.20
Affected products
| Product | Versions |
|---|---|
| OpenPrinting · cups | affected < 2.4.20 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |