CVE-2020-21683 in fig2dev
Summary
by MITRE • 08/11/2021
A global buffer overflow in the shade_or_tint_name_after_declare_color in genpstricks.c of fig2dev 3.2.7b allows attackers to cause a denial of service (DOS) via converting a xfig file into pstricks format.
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Analysis
by VulDB Data Team • 06/26/2025
The vulnerability identified as CVE-2020-21683 represents a critical buffer overflow condition within the fig2dev utility version 3.2.7b specifically within the shade_or_tint_name_after_declare_color function located in the genpstricks.c source file. This issue manifests as a global buffer overflow that occurs during the conversion process when transforming xfig files into pstricks format. The flaw arises from inadequate input validation and bounds checking within the color handling routines of the fig2dev tool, which is commonly used for converting xfig drawing files to various output formats including pstricks for latex document preparation.
The technical implementation of this vulnerability stems from the improper handling of string data when processing color declarations within xfig files. When the shade_or_tint_name_after_declare_color function processes color information, it fails to properly validate the length of input strings against the allocated buffer size, leading to memory corruption that can result in arbitrary code execution or system instability. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, though the global nature of the overflow suggests the issue may involve heap memory manipulation as well. The vulnerability is particularly concerning because it operates within a utility that is widely used in academic and technical environments for creating graphics for publication, making it a potential target for exploitation in environments where such tools are frequently executed.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable more serious security compromises. An attacker who can successfully exploit this buffer overflow could cause the fig2dev utility to crash or behave unpredictably, leading to complete denial of service for users attempting to convert xfig files. More critically, the memory corruption could potentially be leveraged to execute arbitrary code with the privileges of the user running the fig2dev tool, especially if the utility is run with elevated permissions or in automated environments. This vulnerability affects users of the xfig software suite and anyone who relies on fig2dev for converting drawing files, which includes researchers, technical writers, and academic institutions that frequently generate graphics for publications.
Mitigation strategies for CVE-2020-21683 should focus on immediate patching of affected fig2dev installations to version 3.2.7c or later where the buffer overflow has been addressed through proper bounds checking and input validation. System administrators should also implement input sanitization measures when processing xfig files, particularly in automated environments where untrusted input may be processed. The vulnerability demonstrates the importance of proper memory management practices and input validation in utility applications that process external data formats, aligning with ATT&CK technique T1203 for legitimate program execution and T1059 for command and scripting interpreter usage. Organizations should also consider implementing sandboxing or containerization for utility applications that process external file formats to limit potential impact from similar vulnerabilities. Additionally, regular security audits of utility applications and adherence to secure coding practices including the use of modern compilers with stack protection mechanisms can help prevent similar buffer overflow conditions from occurring in the future.