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Fencer Vulns
low 3.0

CVE-2026-87876 json

Cups: openprinting cups: remaining case-insensitive username matching in scheduler side paths (cve-2026-27447 follow-up)

published 2026-09-09 2 mo ago modified 2026-11-07 2 d ago also EUVD-2026-75089

cvss
3.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

Two case-insensitive comparisons on request-derived usernames outside the main authorization path in CUPS's scheduler (printer ACL validation and private-attribute filtering) could allow bypass of username-based access controls in certain configurations.

Patch / fix

  • Red Hat Red Hat Hardened Images 2.4.19-4.2.hum1
  • cups hummingbird 1 2.4.19-4.2.hum1
  • cups-lpd hummingbird 1 2.4.19-4.2.hum1
  • cups-libs hummingbird 1 2.4.19-4.2.hum1
  • cups-client hummingbird 1 2.4.19-4.2.hum1
  • cups-ipptool hummingbird 1 2.4.19-4.2.hum1
  • cups-filesystem hummingbird 1 2.4.19-4.2.hum1
  • cups-printerapp hummingbird 1 2.4.19-4.2.hum1

red hat advisories RHSA-2026:67568

  • 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-2026-87876 updated cvss 3.0

cups: OpenPrinting CUPS: Remaining case-insensitive username matching in scheduler side paths (CVE-2026-27447 follow-up)

  • Red Hat Enterprise Linux 6 cups, cups-lpd, cups-php, cups-libs, cups 2.4.10-18.el10_2 Red Hat Enterprise Linux 7 cups, cups-lpd, cups-libs, cups-client, cups-ipptool, cups-filesystem, +1 more Red Hat Enterprise Linux 8 cups, cups-lpd, cups-libs, cups-client, cups-ipptool, cups-filesystem, +1 more Red Hat Enterprise Linux 9 cups, cups-lpd, cups-libs, rhel9/cups, cups-client, cups-ipptool, +3 more Red Hat Enterprise Linux 10 cups 2.4.10-18.el10_2 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images cups 2.4.19-4.2.hum1, cups-lpd 2.4.19-4.2.hum1, cups-libs 2.4.19-4.2.hum1, cups-client 2.4.19-4.2.hum1, cups-ipptool 2.4.19-4.2.hum1, cups-filesystem 2.4.19-4.2.hum1, +1 more
    fixed: vendor fix RHSA-2026:67568

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
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.0 CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N

Affected products

  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift Container Platform 4

Classification

Weakness
  • CWE-178 Improper Handling of Case Sensitivity

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.