Bug 2531218

Summary: CVE-2026-87876 cups: OpenPrinting CUPS: Remaining case-insensitive username matching in scheduler side paths (CVE-2026-27447 follow-up) [fedora-all]
Product: [Fedora] Fedora Reporter: Melissa Ing <meing>
Component: cupsAssignee: Zdenek Dohnal <zdohnal>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: unspecified    
Version: rawhideCC: twaugh, zdohnal
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["14ca1954-c82a-4b9f-8a6d-6cd324a1e703"]}
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Description Melissa Ing 2026-09-10 01:28:05 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

The OpenPrinting CUPS project contains two instances of case-insensitive username comparisons in authorization-adjacent code paths that were not addressed by the original CVE-2026-27447 fix. These exist in the printer ACL validation logic and private-attribute filtering mechanisms:

1. scheduler/ipp.c:check_quotas() - uses _cups_strcasecmp() for printer ACL username matching
2. scheduler/policy.c:cupsdGetPrivateAttrs() - uses _cups_strcasecmp() for @OWNER and explicit username checks

These patterns were removed from the primary authorization path in the original CVE-2026-27447 fix but persist in these secondary paths.

Affected versions: < 2.4.20. No patched release listed at time of advisory (fixes committed but not yet released).

Reference: https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2