CVE-2009-4013 in Lintian
Summary
by MITRE
Multiple directory traversal vulnerabilities in Lintian 1.23.x through 1.23.28, 1.24.x through 1.24.2.1, and 2.x before 2.3.2 allow remote attackers to overwrite arbitrary files or obtain sensitive information via vectors involving (1) control field names, (2) control field values, and (3) control files of patch systems.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability identified as CVE-2009-4013 represents a critical directory traversal flaw affecting Lintian versions 1.23.x through 1.23.28, 1.24.x through 1.24.2.1, and 2.x versions prior to 2.3.2. This issue stems from inadequate input validation mechanisms within the package validation tool that processes debian package control files. The vulnerability operates by exploiting improper handling of control field names, control field values, and patch system control files, creating opportunities for attackers to manipulate file system operations through crafted malicious inputs. The root cause aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. These vulnerabilities enable attackers to manipulate the file system by including directory traversal sequences in input data, potentially allowing them to access or modify files outside the intended directory structure.
The operational impact of this vulnerability extends beyond simple information disclosure to include arbitrary file overwrite capabilities that could severely compromise system integrity. Attackers exploiting these directory traversal vectors can manipulate control files used by Lintian to validate debian packages, potentially leading to privilege escalation, data corruption, or unauthorized system modifications. The vulnerability affects the core functionality of Lintian as a package validation tool, which is critical for maintaining software quality and security within debian-based distributions. When an attacker successfully exploits these vulnerabilities, they can potentially overwrite system configuration files, inject malicious code into package validation processes, or access sensitive information from the underlying system. The attack surface includes scenarios where Lintian processes user-provided package data, making it particularly dangerous in environments where untrusted packages are validated or when Lintian is used in automated build systems.
The exploitation of CVE-2009-4013 demonstrates the importance of proper input sanitization and access control mechanisms in security-critical applications. From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including TA0005 (Defense Evasion) through file system manipulation and TA0006 (Credential Access) when attackers can obtain sensitive information from system files. The vulnerability exists because Lintian fails to properly validate or sanitize control field names and values before using them in file system operations, allowing attackers to inject malicious path sequences that bypass normal access controls. This flaw particularly affects environments where Lintian is used in automated package building and validation processes, as these systems often run with elevated privileges to perform their validation functions. The vulnerability's impact is amplified by the fact that Lintian is commonly used in continuous integration pipelines and automated package repositories, making successful exploitation potentially widespread across multiple systems.
Mitigation strategies for CVE-2009-4013 require immediate patching of affected Lintian versions to 2.3.2 or later, which contains the necessary fixes for proper input validation and path traversal prevention. Organizations should implement strict input validation policies for all control file processing, including normalization and sanitization of field names and values before any file system operations occur. The fix typically involves implementing proper path validation that rejects or removes directory traversal sequences such as ../ or ..\ from input data before processing. Additionally, system administrators should ensure that Lintian runs with minimal required privileges and that package validation processes are isolated from critical system files. Network segmentation and access controls should be implemented to limit exposure of systems running Lintian to trusted sources only. Security monitoring should include detection of unusual file system access patterns that might indicate exploitation attempts, and regular security audits should verify that no unauthorized file modifications have occurred as a result of potential exploitation. The vulnerability highlights the need for comprehensive security testing of validation tools and the importance of following secure coding practices that prevent path traversal attacks through proper input validation and access control mechanisms.