Affected: OpenPrinting cups

OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, CUPS daemon (cupsd) contains an authorization bypass vulnerability due to case-insensitive username comparison during authorization checks. The vulnerability allows an unprivileged user to gain unauthorized access to restricted operations by using a user with a username that differs only in case from an authorized user. At time of publication, there are no publicly available patches.

Affected: Ubuntu:22.04:LTS: cups, Ubuntu:24.04:LTS: cups, Ubuntu:25.10: cups, Ubuntu:26.04:LTS: cups

Ariel Silver discovered that CUPS incorrectly handled username comparisons during authorization checks. A local attacker could possibly use this issue to gain unauthorized access to restricted operations. (CVE-2026-27447)

Asim Viladi Oglu Manizada discovered that CUPS incorrectly handled notify-recipient-uri values in the RSS notifier. A remote attacker could possibly use this issue to overwrite lp-writable files and cause a denial of service. (CVE-2026-34978)

Jacob Newman discovered that CUPS incorrectly handled filter option strings when processing job attributes. An attacker could use this issue to cause CUPS to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-34979)

Asim Viladi Oglu Manizada discovered that CUPS incorrectly handled page-border values in shared PostScript queues. A remote attacker could possibly use this issue to execute arbitrary code. (CVE-2026-34980)

Asim Viladi Oglu Manizada discovered that CUPS incorrectly handled localhost authentication to attacker-controlled IPP services. A local attacker could possibly use this issue to overwrite arbitrary files and execute arbitrary code. (CVE-2026-34990)

Tomer Fichman discovered that CUPS incorrectly handled negative job-password-supported values. A local attacker could possibly use this issue to cause CUPS to crash, resulting in a denial of service. (CVE-2026-39314)

Tomer Fichman discovered that CUPS incorrectly handled temporary printer deletion. An attacker could p…