CVE-2024-51982 in Printer
Summary
by MITRE • 06/25/2025
An unauthenticated attacker who can connect to TCP port 9100 can issue a Printer Job Language (PJL) command that will crash the target device. The device will reboot, after which the attacker can reissue the command to repeatedly crash the device. A malformed PJL variable FORMLINES is set to a non number value causing the target to crash.
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Analysis
by VulDB Data Team • 06/25/2025
This vulnerability resides in networked printing devices that expose TCP port 9100, which is the standard port for PJL communication. The flaw manifests when an unauthenticated attacker sends a malformed PJL command containing a FORMLINES variable set to a non-numeric value, leading to a device crash and subsequent reboot. This represents a critical denial of service vulnerability that can be exploited without requiring any authentication credentials or privileged access to the network. The device's failure to properly validate input parameters in PJL commands creates a condition where malformed data can trigger a system-level crash, effectively rendering the printer or print server unavailable to legitimate users.
The technical implementation of this vulnerability exploits the printer's insufficient input validation mechanisms specifically within the PJL processing subsystem. When the FORMLINES variable receives a non-numeric value, the device's internal parsing logic fails to handle the unexpected data type gracefully, resulting in a memory corruption or stack overflow condition that causes the system to crash and automatically reboot. This behavior creates a persistent denial of service condition where the attacker can repeatedly send the same malformed command to continuously disrupt printer services, as the device reboots and becomes available for the next attack cycle. The vulnerability affects devices that implement PJL command processing without proper sanitization of input parameters.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect business continuity in environments where print services are critical for operations. Network administrators may find their print servers repeatedly going offline, requiring manual intervention to restore services and potentially disrupting workflows across multiple departments. In large enterprise environments, this could lead to cascading effects where multiple printers become unavailable simultaneously, particularly if the vulnerability affects centralized print servers that manage multiple devices. The repetitive nature of the attack means that automated monitoring systems may not be able to distinguish between legitimate device failures and malicious exploitation attempts, potentially leading to false positive alerts or delayed incident response.
Organizations should implement immediate network segmentation to isolate printer devices from critical network segments, particularly by blocking access to TCP port 9100 from unauthorized networks. Network access control lists should be configured to restrict access to this port to only trusted administrative workstations and management systems. Device firmware updates should be prioritized to address the input validation deficiencies in PJL command processing, with vendors providing patches that properly validate all numeric parameters before processing. Additionally, implementing network monitoring solutions that can detect and alert on unusual patterns of PJL command execution may help identify exploitation attempts. According to the CWE catalog, this vulnerability maps to CWE-129 Input Validation, while the ATT&CK framework would classify this under T1499.004 Endpoint Denial of Service, as it specifically targets endpoint devices to disrupt their availability and functionality.