CUPS before 1.1.21rc1 treats a Location directive in cupsd.conf as case sensitive, which allows attackers to bypass intended ACLs via a printer name containing uppercase or lowercase letters that are different from what is specified in the directive.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
2.1% chance of exploitation in the next 30 days; higher than 81% of CVEs (scores of 2026-10-31)