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Fencer Vulns
low 3.3

CVE-2026-55453 json

CUPS ipp backend status-line injection can update queue PPD and lead to conditional RCE as lp via foomatic-rip

published 2026-10-15 24 d ago modified 2026-10-20 19 d ago also EUVD-2026-102207

cvss
3.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. Prior to 2.4.20, the backend/ipp.c quote_string() function preserves carriage-return and line-feed characters in a remote printer-controlled marker-message before report_attr() writes the value to the scheduler status stream. The scheduler can parse an injected newline as a separate PPD: control line and persist an attacker-selected PPD keyword. The reporter demonstrated that a later print job on a Foomatic-backed queue could consume an injected FoomaticRIPCommandLine value and execute in the filter context as lp. This issue is fixed in version 2.4.20.

Patch / fix

  • openprinting cups 2.4.20
  • cups hummingbird 1 2.4.19-4.6.hum1
  • cups-lpd hummingbird 1 2.4.19-4.6.hum1
  • cups-libs hummingbird 1 2.4.19-4.6.hum1
  • cups-client hummingbird 1 2.4.19-4.6.hum1
  • cups-ipptool hummingbird 1 2.4.19-4.6.hum1
  • cups-filesystem hummingbird 1 2.4.19-4.6.hum1
  • cups-printerapp hummingbird 1 2.4.19-4.6.hum1

red hat advisories RHSA-2026:84421

  • cups openSUSE Tumbleweed 2.4.20-1.1

opensuse advisories openSUSE-SU-2026:12192-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55453 updated cvss 7.5

cups: cups: Arbitrary code execution via newline injection in printer status messages

  • Red Hat Hardened Images cups 2.4.19-4.6.hum1, cups-lpd 2.4.19-4.6.hum1, cups-libs 2.4.19-4.6.hum1, cups-client 2.4.19-4.6.hum1, cups-ipptool 2.4.19-4.6.hum1, cups-filesystem 2.4.19-4.6.hum1, +1 more
    fixed: vendor fix RHSA-2026:84421

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
24 d ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/OpenPrinting/cups/security/advisories/GHSA-7hqf-mfhx-7r3v referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Affected products

  • OpenPrinting cups

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
  • CWE-77 Improper Neutralization of Special Elements used in a Command
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.