CVE-2026-55467

CUPS fax option values bypass the CVE-2026-34980 control-character sanitizer (incomplete fix)

Published Oct 15, 2026 CVSS 3.1 · 2.5 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:openprinting:cups:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Openprinting
Openprinting cups
Vendors & Products Openprinting
Openprinting cups
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title CUPS fax option values bypass the CVE-2026-34980 control-character sanitizer (incomplete fix)
Weaknesses CWE-150
CWE-93
CWE-94
References
Metrics cvssV3_1

{'score': 2.5, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L'}

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 15, 2026, 5:49 PM
Reserved
Jun 16, 2026, 10:10 PM
Status
Analyzed
Published
Oct 15, 2026, 6:17 PM
Modified
Oct 20, 2026, 7:37 PM
Severity
Low
Public date
Oct 15, 2026, 5:08 PM