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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55467
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-15 18:17:27 UTC
Updated2026-10-20 19:37:48 UTC
DescriptionOpenPrinting 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.

Risk And Classification

Primary CVSS: v3.1 2.5 LOW from [email protected]

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

EPSS: 0.001730000 probability, percentile 0.063130000 (date 2026-10-20)

Problem Types: CWE-93 | CWE-94 | CWE-150 | CWE-93 CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection') | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection') | CWE-150 CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary2.5LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
3.1CNADECLARED2.5LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Openprinting Cups All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA OpenPrinting Cups affected < 2.4.20 Not specified

References

ReferenceSourceLinkTags
github.com/OpenPrinting/cups/commit/0cf4e7814d6810ed3c454222bce3aa342d54... [email protected] github.com Patch
github.com/OpenPrinting/cups/security/advisories/GHSA-69qc-prxg-h2c7 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Exploit, Vendor Advisory
github.com/OpenPrinting/cups/commit/a9e7e7a3a019d0fa063d29409d3f82e4c6d5... [email protected] github.com Patch
github.com/OpenPrinting/cups/releases/tag/v2.4.20 [email protected] github.com Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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