Executive brief
OpenPrinting CUPS is a widely used open-source printing system for Linux and Unix-like operating systems. A vulnerability in how it handles shared printer queues allows an unauthenticated attacker to remotely execute arbitrary commands on the system. This could lead to a complete system takeover, unauthorized data access, or service disruption, especially when combined with other known flaws.
Technical details
A vulnerability in OpenPrinting CUPS (versions 2.4.16 and prior) allows an unauthenticated remote attacker to achieve code execution as the 'lp' user. The flaw exists in the cupsd scheduler when a shared PostScript queue is exposed. An attacker can send a Print-Job with a specially crafted 'page-border' value containing an embedded newline. When the server escapes and later reparses this value, it interprets the second line as a trusted 'PPD:' scheduler control record. By injecting a 'cupsFilter2' entry into the queue's PPD file, the attacker can force the server to execute an arbitrary binary during a subsequent raw print job. This can be chained with other vulnerabilities to escalate privileges to root.
Affected products
- OpenPrinting CUPS <= 2.4.16
Timeline
- 2026-03-31: advisory: Initial advisory published by OpenPrinting
- 2026-04-03: disclosed: CVE-2026-34980 assigned and published