CVE-2025-65079: Lexmark PostScript Buffer Overflow Flaw

CVE-2025-65079 Overview

A heap-based buffer overflow vulnerability has been identified in the Postscript interpreter in various Lexmark devices. This vulnerability can be leveraged by an attacker to execute arbitrary code as an unprivileged user. The flaw exists in the Postscript processing functionality and can be exploited remotely over the network without requiring authentication.

Critical Impact

Successful exploitation allows remote attackers to execute arbitrary code on affected Lexmark devices, potentially compromising print infrastructure and enabling lateral movement within enterprise networks.

Affected Products

• Lexmark devices with Postscript interpreter functionality
• Various Lexmark printer and multifunction device models
• Devices running vulnerable firmware versions

Discovery Timeline

• 2026-02-03 - CVE-2025-65079 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2025-65079

Vulnerability Analysis

This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), a memory corruption flaw that occurs when data is written beyond the allocated buffer in the heap memory region. In the context of Lexmark devices, the vulnerability resides within the Postscript interpreter component, which processes Postscript print jobs and documents.

The Postscript interpreter fails to properly validate the size or boundaries of input data when processing certain Postscript commands or document elements. When a specially crafted Postscript file is submitted to a vulnerable device, it can trigger the overflow condition, allowing an attacker to overwrite adjacent heap memory structures.

Root Cause

The root cause stems from insufficient bounds checking in the Postscript interpreter's memory allocation and data handling routines. When processing Postscript jobs, the interpreter allocates heap memory for various data structures. The vulnerability occurs when the interpreter writes data that exceeds the allocated buffer size without proper validation, corrupting heap metadata or adjacent memory regions.

This type of vulnerability is particularly dangerous in embedded systems like printers, where security controls are often more limited than in traditional computing environments.

Attack Vector

The attack vector is network-based, meaning an attacker can remotely exploit this vulnerability without requiring physical access to the device. The attack can be conducted by:

1. Submitting a malicious Postscript document to the printer via network printing protocols (LPD, IPP, raw port 9100)
2. Sending the crafted payload through print server queues
3. Exploiting the vulnerability through direct network access to the printer's services

The attacker does not require authentication to exploit this vulnerability, making it accessible to any network user who can reach the device. Successful exploitation results in arbitrary code execution with the privileges of the Postscript interpreter process.

The vulnerability can be triggered by embedding specially crafted Postscript operators or data structures within a print job that causes the interpreter to write beyond allocated heap boundaries. This memory corruption can be leveraged to gain control of program execution flow and execute attacker-supplied code.

Detection Methods for CVE-2025-65079

Indicators of Compromise

• Unexpected printer reboots or crashes when processing certain print jobs
• Unusual network traffic patterns from printer devices to external hosts
• Anomalous process behavior or memory utilization on Lexmark devices
• Print queue errors or failed jobs with malformed Postscript files

Detection Strategies

• Monitor network traffic to printers for unusually large or malformed Postscript documents
• Implement network segmentation to isolate print infrastructure and enable traffic inspection
• Deploy intrusion detection signatures to identify exploitation attempts targeting Postscript interpreters
• Review printer logs for repeated processing errors or crash events

Monitoring Recommendations

• Enable logging on print servers to track job submissions and source addresses
• Configure SIEM alerts for abnormal printer device behavior patterns
• Monitor for unauthorized configuration changes on Lexmark devices
• Track firmware versions across the printer fleet to identify vulnerable devices

How to Mitigate CVE-2025-65079

Immediate Actions Required

• Check the Lexmark Security Advisories page for firmware updates addressing this vulnerability
• Implement network access controls to restrict printer access to authorized hosts only
• Disable unnecessary network protocols on Lexmark devices where possible
• Segment printer networks from sensitive corporate infrastructure

Patch Information

Lexmark has published security advisories addressing this vulnerability. Administrators should consult the official Lexmark Security Advisories page for the latest firmware versions that remediate CVE-2025-65079. Apply the recommended firmware updates to all affected devices in accordance with your organization's change management procedures.

Workarounds

• Restrict network access to Lexmark devices using firewall rules or access control lists
• Disable Postscript processing if not required and use alternative print formats (PCL)
• Implement print job filtering at the print server level to inspect incoming documents
• Consider placing printers on isolated VLANs with restricted internet access