CVE-2026-55453 CUPS ipp backend status-line injection can update queue PPD and lead to conditional RCE as lp via foomatic-rip
Remote attackers can inject newlines into IPP responses to modify PPD settings, leading to command execution as the lp user via Foomatic filters.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55453?
CVE-2026-55453 is a low-severity command injection vulnerability in OpenPrinting cups, published on 15 Oct 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
OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. Prior to 2.4.20, the backend/ipp.c quote_string() function preserves carriage-return and line-feed characters in a remote printer-controlled marker-message before report_attr() writes the value to the scheduler status stream. The scheduler can parse an injected newline as a separate PPD: control line and persist an attacker-selected PPD keyword. The reporter demonstrated that a later print job on a Foomatic-backed queue could consume an injected FoomaticRIPCommandLine value and execute in the filter context as lp. This issue is fixed in version 2.4.20.
Which versions are affected by CVE-2026-55453?
It affects 1 product.
Products include Openprinting Cups.
How do I fix CVE-2026-55453?
Upgrade to a fixed version.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-55453 being exploited?
There is no known exploitation of CVE-2026-55453 in the wild and no public exploit code.
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 AZL-108287, BELL-CVE-2026-55453, CLSA-2026-1792768682, CLSA-2026-1792768763, DEBIAN-CVE-2026-55453, ECHO-e4db-2416-74ec and 2 more.