Description
OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. Prior to 2.4.20, the cupsdCreateJob option-string builder in scheduler/job.c maps attacker-controlled destination-uri and pre-dial-string values from a configured fax queue to the phone and faxPrefix options. Unlike ordinary IPP job attributes, these mapped fax values bypass the control-character sanitizer and are copied directly into the filter options argument. A user permitted to submit a job can therefore inject control characters into the downstream option stream. The reporter states that a downstream fax filter passing these values to a shell or modem command could execute code as lp, while the maintainer states that CUPS has no confidentiality or integrity impact because the only known code-executing filter is optional Foomatic and addressed separately, leaving possible disruption of the affected queue. This issue is fixed in version 2.4.20.
Affected products
openprinting: cups
References5
- github.com/OpenPrinting/cups/security/advisories/GHSA-69qc-prxg… ExploitVendor Advisory
- github.com/OpenPrinting/cups/security/advisories/GHSA-69qc-prxg… ExploitVendor Advisory
- github.com/OpenPrinting/cups/commit/0cf4e7814d6810ed3c454222bce… Patch
- github.com/OpenPrinting/cups/commit/a9e7e7a3a019d0fa063d29409d3… Patch
- github.com/OpenPrinting/cups/releases/tag/v2.4.20 Release Notes
Metrics
- CVSS 3.1
-
2.5
LOW
Score source: CNA
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L - EPSS — exploit probability
- 0% percentile: 8 · as of 10 November 2026
- CWE
- CWE-93CWE-94CWE-150
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