CVE-2026-55480
CUPS copy_model() creates a predictable PPD tempfile without O_EXCL/O_NOFOLLOW (symlink TOCTOU, lp → root)
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.
INFO
Published Date :
Oct. 15, 2026, 6:17 p.m.
Last Modified :
Oct. 15, 2026, 6:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update CUPS to version 2.4.20 or later.
- Apply vendor patches if available.
- Restrict write access to temporary directories.
- Monitor for suspicious file modifications.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55480.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55480 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55480
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-55480 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55480 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Oct. 15, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H Added CWE CWE-59 Added CWE CWE-377 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55480.json">CVE-2026-55480</a> Added Reference https://github.com/OpenPrinting/cups/commit/98adfd855950e806508f961d5438ad32e26aac62 Added Reference https://github.com/OpenPrinting/cups/commit/f6a11dae0f0f3b748fbca931e237be03ffe8e48e Added Reference https://github.com/OpenPrinting/cups/releases/tag/v2.4.20 Added Reference https://github.com/OpenPrinting/cups/security/advisories/GHSA-jj94-x3qh-ffp9