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Fencer Intel
high 8.8

CVE-2018-6553 json

AppArmor cupsd Sandbox Bypass Due to Use of Hard Links

published 2018-08-10 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-18305

cvss
8.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

The CUPS AppArmor profile incorrectly confined the dnssd backend due to use of hard links. A local attacker could possibly use this issue to escape confinement. This flaw affects versions prior to 2.2.7-1ubuntu2.1 in Ubuntu 18.04 LTS, prior to 2.2.4-7ubuntu3.1 in Ubuntu 17.10, prior to 2.1.3-4ubuntu0.5 in Ubuntu 16.04 LTS, and prior to 1.7.2-0ubuntu1.10 in Ubuntu 14.04 LTS.

Patch / fix

  • n/a cups 1.7.2-0ubuntu1.10, 2.1.3-4ubuntu0.5, 2.2.4-7ubuntu3.1, 2.2.7-1ubuntu2.1
  • cups Debian 14, Debian 13, Debian 12 2.2.8-5

debian advisories DEBIAN-CVE-2018-6553

  • cups Ubuntu 14.04 LTS 1.7.2-0ubuntu1.10
  • cups Ubuntu 16.04 LTS 2.1.3-4ubuntu0.5
  • cups Ubuntu 18.04 LTS 2.2.7-1ubuntu2.1

ubuntu advisories UBUNTU-CVE-2018-6553

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2018-6553 updated cvss 7.0

cups: AppArmor cupsd Sandbox Bypass Due to Use of Hard Links

  • Red Hat Enterprise Linux 5 cups Red Hat Enterprise Linux 6 cups, cups-lpd, cups-php, cups-libs Red Hat Enterprise Linux 7 cups, cups-lpd, cups-libs, cups-client, cups-ipptool, cups-filesystem Red Hat Enterprise Linux 8 cups, cups-lpd, cups-libs, cups-client, cups-ipptool, cups-filesystem Red Hat Virtualization 4 cups
    not affected: vulnerable code not present

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

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 8.8 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • n/a cups

References

Sources

Fencer Intel 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.