CVE-2026-87876
Cups: openprinting cups: remaining case-insensitive username matching in scheduler side paths (cve-2026-27447 follow-up)
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.
Fixes and workarounds
Workaround
Fixed on upstream master branch with commit f56844d and for versions 2.4.x with commit 88e67c0.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Hardened Images Red Hat cups-main
https://catalog.redhat.com/software/containers/ |
≥ 2.4.19-4.2.hum1; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 10 Red Hat cups
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 6 Red Hat cups
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat cups
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat cups
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat cups
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat rhel9/cups
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-8
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 3.0 low |
CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N | CNA: redhat |
Exploit evidence
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2
exploit · ADP: CISA-ADP
References
- https://access.redhat.com/errata/RHSA-2026:67568CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-87876CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2530991CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://github.com/OpenPrinting/cups/commit/88e67c00c130a45f3a1edf36686f7a0b2982fef8CNA: redhat
- https://github.com/OpenPrinting/cups/commit/f56844dbe4a54a9f8e1aeb3b913fbee614156bdbCNA: redhat
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2CNA: redhat
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2ADP: CISA-ADP · exploit
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