OpenPrinting CUPS up to 2.4.19 Option String Builder scheduler/job.c cupsdCreateJob destination-uri/pre-dial-string injection

Summaryinfo

A vulnerability classified as critical was found in OpenPrinting CUPS up to 2.4.19. This vulnerability affects the function cupsdCreateJob of the file scheduler/job.c of the component Option String Builder. Executing a manipulation of the argument destination-uri/pre-dial-string can lead to injection. This vulnerability is tracked as CVE-2026-55467. The attack is restricted to local execution. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in OpenPrinting CUPS up to 2.4.19. This vulnerability affects the function cupsdCreateJob of the file scheduler/job.c of the component Option String Builder. The manipulation of the argument destination-uri/pre-dial-string with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-55467 since 06/17/2026. The exploitation appears to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1055 by the MITRE ATT&CK project.

Upgrading to version 2.4.20 eliminates this vulnerability.

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Productinfo

Type

• Printing Software

Vendor

• OpenPrinting

Name

• CUPS

Version

• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3
• 2.4.4
• 2.4.5
• 2.4.6
• 2.4.7
• 2.4.8
• 2.4.9
• 2.4.10
• 2.4.11
• 2.4.12
• 2.4.13
• 2.4.14
• 2.4.15
• 2.4.16
• 2.4.17
• 2.4.18
• 2.4.19

Website

• Product: https://github.com/OpenPrinting/cups/

CPE 2.3info

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CPE 2.2info

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