CVE-2022-2085 in Ghostscript
Summary
by MITRE • 06/16/2022
A NULL pointer dereference vulnerability was found in Ghostscript, which occurs when it tries to render a large number of bits in memory. When allocating a buffer device, it relies on an init_device_procs defined for the device that uses it as a prototype that depends upon the number of bits per pixel. For bpp > 64, mem_x_device is used and does not have an init_device_procs defined. This flaw allows an attacker to parse a large number of bits (more than 64 bits per pixel), which triggers a NULL pointer dereference flaw, causing an application to crash.
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Analysis
by VulDB Data Team • 05/24/2026
The vulnerability identified as CVE-2022-2085 represents a critical NULL pointer dereference flaw within the Ghostscript PDF rendering engine that operates at the intersection of memory management and device initialization processes. This weakness manifests when the software attempts to handle high-bit-depth graphics processing, specifically when dealing with pixel configurations exceeding 64 bits per pixel. The root cause lies in the software's buffer device allocation mechanism where the system relies on init_device_procs function pointers that define device-specific processing procedures. When bpp values exceed the 64-bit threshold, the system defaults to using mem_x_device which lacks the essential init_device_procs definition, creating a scenario where dereferencing a null pointer becomes inevitable during the rendering process.
The technical exploitation of this vulnerability occurs through carefully crafted malicious PDF files or graphics content that forces Ghostscript to allocate memory buffers with bit depths greater than 64 bits per pixel. This specific condition triggers a cascading failure where the system attempts to access a function pointer that has not been initialized, resulting in immediate application termination. The flaw demonstrates poor error handling and validation within the device initialization framework, where the software fails to properly validate bit depth parameters before proceeding with memory allocation operations. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions, and represents a classic example of inadequate input validation in graphics processing pipelines. The vulnerability is particularly concerning because it can be triggered through standard PDF rendering operations without requiring special privileges or complex attack vectors.
From an operational perspective, this vulnerability creates significant risks for organizations that rely on Ghostscript for document processing, particularly in environments where untrusted PDF files are processed automatically. The crash behavior can be leveraged for denial-of-service attacks against systems that depend on Ghostscript for PDF rendering, potentially disrupting document workflows in enterprise environments, web applications, or print servers. The impact extends beyond simple application crashes to include potential service disruption for critical infrastructure that depends on reliable PDF processing capabilities. Security practitioners should note that this vulnerability can be exploited in automated environments where PDF files are processed in bulk, making it particularly dangerous for email servers, document management systems, or web applications that handle user-uploaded PDF content. The vulnerability's exploitation requires minimal skill and can be automated, making it attractive to threat actors seeking to disrupt services.
Mitigation strategies for CVE-2022-2085 should focus on immediate patch application from the vendor, as the fix typically involves proper validation of bit depth parameters and ensuring that all device types have appropriate initialization procedures. Organizations should implement input validation measures that restrict bit depth values to supported ranges, particularly those below 64 bits per pixel where the vulnerability is not present. Network segmentation and application whitelisting can help limit exposure by preventing unauthorized access to systems running Ghostscript. Additionally, deploying intrusion detection systems that monitor for suspicious PDF processing patterns may help identify exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499 which covers network disruption, and T1059 which covers command and scripting interface usage in exploitation contexts. Regular security assessments should include testing for similar memory management flaws in graphics processing libraries, as this represents a common class of vulnerabilities in multimedia and document rendering software.