CVE-2026-87876 Auth bypass in Red Hat Enterprise Linux 10
Attackers can bypass username-based access controls in CUPS scheduler paths due to case-insensitive comparisons, potentially accessing restricted printer resources.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-87876?
CVE-2026-87876 is a low-severity authentication bypass vulnerability in Red Hat Enterprise Linux 10, published on 9 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-178
Which versions are affected by CVE-2026-87876?
Linux distribution packages (8)
cups Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-client Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-devel Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-filesystem Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-ipptool Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-libs Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-lpd Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
cups-printerapp Red Hat:hummingbird:1 | All versions | 0:2.4.19-4.2.hum1 |
How do I fix CVE-2026-87876?
Apply the vendor's patch.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-87876 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-87876 exists.
Sources
Also known as AZL-100923, BELL-CVE-2026-87876, DEBIAN-CVE-2026-87876, ECHO-0636-b260-0d3d, GHSA-r8jp-q6fh-g5r2, RHSA-2026:67568 and 1 more.