CVE-2019-3835 in Ghostscript
Summary
by MITRE
It was found that the superexec operator was available in the internal dictionary in ghostscript before 9.27. A specially crafted PostScript file could use this flaw in order to, for example, have access to the file system outside of the constrains imposed by -dSAFER.
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Analysis
by VulDB Data Team • 06/17/2025
The vulnerability identified as CVE-2019-3835 represents a critical security flaw within the Ghostscript document processing software ecosystem. This issue affects versions prior to 9.27 and stems from an improper implementation of the superexec operator within the internal dictionary structure. The superexec operator, when improperly exposed or accessible, creates an unintended pathway for malicious PostScript code to bypass fundamental security restrictions that are typically enforced by the -dSAFER parameter. This parameter is designed to prevent unauthorized access to the file system and other system resources during PostScript execution, serving as a crucial sandboxing mechanism for document processing applications.
The technical exploitation of this vulnerability occurs through carefully crafted PostScript files that leverage the accessible superexec operator to escalate privileges beyond the intended security boundaries. When a malicious PostScript document is processed by an affected Ghostscript version, the superexec operator can be invoked to execute commands that would normally be restricted by the -dSAFER sandboxing mechanism. This allows attackers to access file system resources outside the designated safe zones, potentially enabling read access to sensitive files, execution of arbitrary code, or other unauthorized system operations that should be prevented by the security configuration.
The operational impact of CVE-2019-3835 extends beyond simple privilege escalation, as it fundamentally undermines the security model that Ghostscript implements to protect systems from malicious document processing. This vulnerability affects any application that relies on Ghostscript for PostScript and PDF processing, including web applications, document management systems, and enterprise printing solutions. The flaw is particularly concerning because it operates at the core of Ghostscript's interpreter, making it difficult to detect and mitigate without proper version updates or security patches. The vulnerability aligns with CWE-264, which addresses permissions, privileges, and access control issues in software systems, and can be mapped to ATT&CK technique T1059 for execution through PostScript scripting.
Organizations utilizing Ghostscript for document processing must prioritize immediate remediation of this vulnerability through patching to version 9.27 or later, which properly restricts access to the superexec operator. Additional mitigations include implementing strict input validation for PostScript documents, deploying network segmentation to limit access to affected systems, and configuring proper file system permissions to minimize potential damage from successful exploitation. The vulnerability demonstrates the critical importance of maintaining up-to-date security software and highlights the risks associated with improper access control implementation in interpreter-based systems. Security teams should also consider monitoring for suspicious document processing activities and implementing automated patch management systems to prevent exploitation of similar vulnerabilities in the future.