CVE-2013-6476 in Linux
Summary
by MITRE
The OPVPWrapper::loadDriver function in oprs/OPVPWrapper.cxx in the pdftoopvp filter in CUPS and cups-filters before 1.0.47 allows local users to gain privileges via a Trojan horse driver in the same directory as the PDF file.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/08/2026
The vulnerability described in CVE-2013-6476 represents a critical privilege escalation flaw affecting the Common Unix Printing System and its associated cups-filters package. This issue resides within the OPVPWrapper::loadDriver function located in the oprs/OPVPWrapper.cxx file, specifically within the pdftoopvp filter component. The vulnerability stems from inadequate input validation and insecure directory handling mechanisms that allow malicious actors to exploit the system through a carefully crafted Trojan horse driver file placed in the same directory as a target PDF document. The flaw operates by leveraging the trust relationship between the printing system and driver loading processes, where the system automatically loads and executes driver files without proper verification of their authenticity or origin.
The technical implementation of this vulnerability follows a classic path of privilege escalation through insecure file handling. When a user submits a PDF file for printing, the pdftoopvp filter processes the document and attempts to load driver files from the same directory. The OPVPWrapper::loadDriver function does not properly validate the driver file path or verify the integrity of the driver being loaded. This creates an opportunity for local attackers to place a malicious driver file named identically to a legitimate driver in the same directory as the PDF, causing the system to execute the attacker-controlled code with elevated privileges. The vulnerability specifically affects versions prior to 1.0.47 of cups-filters, indicating that this was a known issue that required patching within the printing stack ecosystem.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and unauthorized access to sensitive resources. Local users who can write to directories containing PDF files can leverage this vulnerability to execute arbitrary code with the privileges of the printing system process, which typically runs with elevated permissions. This creates a significant security risk as the attacker can potentially access system files, modify configurations, or establish persistent access mechanisms. The vulnerability operates at the file system level and can be exploited through common attack vectors such as shared directories, temporary file locations, or any scenario where untrusted users have write access to locations containing PDF documents. The attack requires minimal sophistication and can be automated, making it particularly dangerous in environments where multiple users share common directories.
Mitigation strategies for CVE-2013-6476 should focus on implementing proper input validation and secure file handling practices within the printing system components. The most effective immediate solution involves updating to cups-filters version 1.0.47 or later, which contains the necessary patches to address the insecure directory traversal and driver loading mechanisms. System administrators should also implement strict directory permissions and access controls to limit write access to PDF processing directories. Additional protective measures include deploying file integrity monitoring systems, implementing mandatory access controls, and ensuring that printing system processes run with the principle of least privilege. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and follows ATT&CK technique T1068, which involves exploiting local privilege escalation vulnerabilities. Organizations should also consider implementing network segmentation and monitoring for suspicious file creation patterns in printing-related directories to detect potential exploitation attempts.