CVE-2021-26543 in git-parse
Summary
by MITRE • 05/06/2021
The "gitDiff" function in Wayfair git-parse
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Analysis
by VulDB Data Team • 05/12/2021
The CVE-2021-26543 vulnerability resides within the gitDiff function of Wayfair's git-parse library, representing a critical security flaw that impacts the parsing and processing of git repository data. This vulnerability specifically affects how the library handles diff operations and can be exploited through maliciously crafted input that manipulates the diff parsing logic. The issue stems from insufficient input validation and sanitization within the gitDiff function, creating an environment where untrusted data can influence the execution flow and potentially lead to arbitrary code execution or information disclosure. The vulnerability is particularly concerning because git-parse is widely used in continuous integration pipelines and automated deployment systems where it processes diffs from various sources including user-submitted code changes.
The technical implementation of this vulnerability involves a path traversal or command injection vector that occurs when the gitDiff function processes diff data without proper sanitization of special characters or control sequences. Attackers can craft malicious diff inputs that contain sequences designed to manipulate the underlying git commands executed by the library. When the library processes these inputs through its gitDiff function, it fails to properly escape or validate the data, allowing attackers to inject arbitrary commands or manipulate the diff processing logic. This flaw operates at the intersection of input validation and command execution, creating a scenario where the parsing library becomes an attack surface for remote code execution. The vulnerability is categorized under CWE-78 as a command injection weakness, which aligns with the typical exploitation patterns of such flaws in version control parsing libraries.
The operational impact of CVE-2021-26543 extends beyond simple code execution to encompass broader system compromise and data integrity violations. Organizations utilizing git-parse in their CI/CD pipelines, automated testing environments, or code review systems face significant risk when this vulnerability is exploited. The attack can lead to unauthorized access to source code repositories, potential disclosure of sensitive information, and in severe cases, complete system compromise through the execution of malicious commands on the host system. The vulnerability affects the integrity of the diff processing pipeline, potentially allowing attackers to manipulate code analysis results, bypass security checks, or introduce backdoors through carefully crafted diff inputs. This makes the vulnerability particularly dangerous in environments where automated security scanning relies on accurate diff processing to identify vulnerabilities or security issues.
Mitigation strategies for CVE-2021-26543 should focus on immediate patching of the affected git-parse library to address the input validation issues within the gitDiff function. Organizations should implement strict input sanitization measures and ensure that all diff data is properly escaped before processing. The implementation of proper access controls and network segmentation around systems that utilize git-parse can limit the potential impact of exploitation. Additionally, organizations should conduct thorough security assessments of their CI/CD pipelines to identify other potential attack vectors that could leverage similar input handling vulnerabilities. Security monitoring should be enhanced to detect anomalous diff processing patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in parsing libraries and highlights the need for comprehensive input validation, particularly in systems that interface with version control systems where user input can directly influence command execution. Organizations should also consider implementing automated security scanning tools that can detect and flag potentially malicious diff inputs in their automated workflows.