CVE-2025-27836: Artifex Ghostscript Buffer Overflow Flaw

CVE-2025-27836 Overview

A buffer overflow vulnerability has been discovered in Artifex Ghostscript before version 10.05.0. The vulnerability exists in the BJ10V device driver implementation within the contrib/japanese/gdev10v.c source file. This memory corruption flaw allows attackers to overflow a Print buffer, potentially leading to arbitrary code execution or system compromise.

Critical Impact

This buffer overflow vulnerability in Ghostscript's BJ10V printer device driver can be exploited remotely without authentication, potentially allowing attackers to execute arbitrary code with the privileges of the Ghostscript process.

Affected Products

• Artifex Ghostscript versions prior to 10.05.0
• Systems using the BJ10V device driver (gdev10v.c)
• Linux distributions including Debian that package vulnerable Ghostscript versions

Discovery Timeline

• 2025-03-25 - CVE-2025-27836 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-27836

Vulnerability Analysis

This vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input), commonly known as a classic buffer overflow. The flaw resides in the BJ10V device driver code located in contrib/japanese/gdev10v.c, which is part of Ghostscript's contributed printer driver collection for Japanese Canon BJ10V series printers.

Buffer overflow vulnerabilities of this nature occur when data is written to a fixed-size buffer without proper bounds checking. In the context of Ghostscript, this vulnerability can be triggered during document processing when the BJ10V device driver handles print operations that exceed the allocated buffer capacity.

Root Cause

The root cause of CVE-2025-27836 is improper bounds checking in the Print buffer within the BJ10V device driver implementation. The gdev10v.c source file contains code that copies data into a fixed-size buffer without validating that the input data fits within the allocated space. This allows an attacker to provide specially crafted input that overflows the buffer boundaries, potentially overwriting adjacent memory regions including return addresses or function pointers.

Attack Vector

The vulnerability can be exploited remotely via network-accessible attack vectors. An attacker can craft a malicious PostScript or PDF document that, when processed by Ghostscript with the BJ10V device driver, triggers the buffer overflow condition. The attack requires no prior authentication or user interaction, making it particularly dangerous in environments where Ghostscript processes untrusted documents automatically.

Attack scenarios include:

• Processing malicious PostScript/PDF files through web applications using Ghostscript
• Email attachment processing systems that use Ghostscript for document conversion
• Print servers and document management systems leveraging Ghostscript backends

The vulnerability mechanism involves the Print buffer in the BJ10V device driver failing to validate input size before copying data. When a malicious document is processed, oversized data overwrites memory beyond the buffer boundary. For detailed technical information, refer to the Ghostscript Bug Report #708192.

Detection Methods for CVE-2025-27836

Indicators of Compromise

• Ghostscript process crashes or abnormal terminations during document processing
• Unexpected memory access violations or segmentation faults in Ghostscript logs
• Anomalous Ghostscript child processes or unexpected system calls
• Memory corruption artifacts in core dumps associated with Ghostscript

Detection Strategies

• Monitor Ghostscript process behavior for signs of memory corruption or unexpected crashes
• Implement file integrity monitoring on Ghostscript binary and configuration files
• Deploy network-level inspection for potentially malicious PostScript/PDF documents targeting document processing systems
• Configure application whitelisting to detect unauthorized code execution from Ghostscript context

Monitoring Recommendations

• Enable verbose logging for Ghostscript processes to capture processing errors and anomalies
• Implement runtime application self-protection (RASP) for systems processing untrusted documents
• Monitor system resource usage for Ghostscript processes to detect exploitation attempts
• Configure security information and event management (SIEM) alerts for Ghostscript-related security events

How to Mitigate CVE-2025-27836

Immediate Actions Required

• Upgrade Artifex Ghostscript to version 10.05.0 or later immediately
• Disable or remove the BJ10V device driver if not required for operations
• Implement input validation and sandboxing for document processing workflows
• Restrict network access to systems running vulnerable Ghostscript versions

Patch Information

Artifex has addressed this vulnerability in Ghostscript version 10.05.0. Organizations should prioritize upgrading to this version or later. The official bug report with patch details is available at the Ghostscript Bug Tracker. Debian users should consult the Debian LTS Security Announcement for distribution-specific patch information.

Workarounds

• Run Ghostscript in a sandboxed environment or container with restricted privileges
• Use the -dSAFER flag when invoking Ghostscript to enable safer processing mode
• Implement network segmentation to isolate document processing systems from untrusted networks
• Configure AppArmor or SELinux policies to restrict Ghostscript process capabilities

# Configuration example
# Run Ghostscript with safer mode and restricted device access
gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=output.pdf input.ps

# Disable the BJ10V device by recompiling Ghostscript without contrib drivers
# or use AppArmor/SELinux to restrict access to gdev10v functionality