---
id: CVE-2026-87876
title: >-
  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 certai…
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 certai…
severity: low
cvss: 3
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N'
cwe:
  - CWE-178
vendor: Red Hat
product: cups-main
affected:
  - cups-main (all versions)
  - cups (all versions)
  - cups (all versions)
  - cups (all versions)
  - cups (all versions)
  - cups (all versions)
  - rhel9/cups (all versions)
  - rhcos/rhcos (all versions)
published: '2026-09-09'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T12:17:22.543'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-87876'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:67568'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-87876'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2530991'
    label: secalert@redhat.com
  - url: >-
      https://github.com/OpenPrinting/cups/commit/88e67c00c130a45f3a1edf36686f7a0b2982fef8
    label: secalert@redhat.com
  - url: >-
      https://github.com/OpenPrinting/cups/commit/f56844dbe4a54a9f8e1aeb3b913fbee614156bdb
    label: secalert@redhat.com
  - url: >-
      https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2
    label: secalert@redhat.com
  - url: >-
      https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-87876.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-87876'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-87876'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-09T18:09:43.830591Z'
epss: 0.00328
epssPercentile: 0.23122
ingestedAt: '2026-09-11T14:42:19.866Z'
patched:
  - hardened_images
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:67568** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67568)
- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-87876.json)