CVE-2026-27447 OpenPrinting CUPS: Authorization bypass via case-insensitive group-member lookup
Unprivileged users can bypass authorization checks in CUPS by exploiting case-insensitive username comparisons to access restricted operations.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-27447?
CVE-2026-27447 is a medium-severity authentication bypass vulnerability in OpenPrinting cups, published on 3 Apr 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-863
Which versions are affected by CVE-2026-27447?
It affects 1 product.
Products include Openprinting Cups.
How do I fix CVE-2026-27447?
No fix published yet.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-27447 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27447 exists.
Other vulnerabilities in OpenPrinting cups
- CVE-2025-58060 cups has Authentication bypass with AuthType Negotiate
- CVE-2026-34978 Path traversal in cups
- CVE-2025-58364 cups: Remote DoS via null dereference
- CVE-2026-34980 OpenPrinting CUPS: Shared PostScript queue lets anonymous Print-Job requests reach `lp` code execution over the network
- CVE-2025-61915 OpenPrinting CUPS vulnerable to stack based out-of-bound write
Sources
Also known as ALPINE-CVE-2026-27447, AZL-81822, BELL-CVE-2026-27447, CLSA-2026-1778141904, CLSA-2026-1778142413, CLSA-2026-1778253061 and 11 more.