CVE-2022-35039 in OTFCC
Summary
by MITRE • 09/22/2022
OTFCC commit 617837b was discovered to contain a heap buffer overflow via /release-x64/otfccdump+0x6e20a0.
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Analysis
by VulDB Data Team • 05/28/2025
The vulnerability identified as CVE-2022-35039 represents a critical heap buffer overflow flaw within the OTFCC (OpenType Font Compiler Collection) software suite. This issue manifests specifically within the otffcdump utility at the memory address /release-x64/otfccdump+0x6e20a0, indicating a memory corruption vulnerability that could potentially be exploited by malicious actors. The flaw exists in the handling of font data processing, where insufficient bounds checking allows for memory writes beyond allocated buffer boundaries. This type of vulnerability falls under the category of memory safety issues commonly classified as CWE-121, which deals with stack-based buffer overflow conditions, though in this case the overflow occurs in heap memory management. The vulnerability impacts the font processing pipeline of OTFCC, which is used for converting and manipulating OpenType font files, making it particularly concerning for systems that process large volumes of font data.
The technical exploitation of this heap buffer overflow occurs when the otffcdump utility processes malformed or specially crafted font files that trigger improper memory allocation and handling. The overflow happens during the parsing of font table structures, where the software fails to validate the size of data segments before attempting to copy or process them into fixed-size buffers. This allows an attacker to overwrite adjacent heap memory regions, potentially leading to arbitrary code execution or application crashes. The vulnerability's location within the release-x64 build suggests it affects the optimized version of the software, making it particularly dangerous in production environments where performance optimizations might mask underlying security flaws. The heap-based nature of this overflow also means that the attack surface extends beyond simple code execution to include memory corruption that could be leveraged for more sophisticated attacks such as information disclosure or privilege escalation.
The operational impact of CVE-2022-35039 extends significantly beyond immediate system stability concerns, particularly in environments where font processing is automated or integrated into larger workflows. Systems that process untrusted font files, such as web servers, content management systems, or document processing pipelines, become vulnerable to remote code execution attacks. This vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access, and T1059, which covers command and control through application execution. The attack vector typically involves sending specially crafted font files to systems that utilize OTFCC for font conversion or validation, potentially allowing attackers to execute arbitrary code on the target system. Organizations using this software in production environments face significant risk, as the vulnerability can be triggered through legitimate font processing workflows without requiring user interaction, making it particularly dangerous for automated processing systems.
Mitigation strategies for CVE-2022-35039 should focus on immediate patching of the OTFCC software to address the heap buffer overflow vulnerability. Organizations should implement strict input validation for all font files processed through OTFCC, including signature verification and size limitations to prevent exploitation attempts. Network segmentation and access controls should be implemented to limit exposure of systems that process font data, particularly those accessible from untrusted networks. Regular security assessments should be conducted to identify other potential vulnerabilities in font processing pipelines, and automated monitoring systems should be deployed to detect anomalous behavior that might indicate exploitation attempts. The vulnerability also highlights the importance of applying security patches promptly, as demonstrated by the specific commit reference 617837b which likely contains the fix for this issue. Additionally, implementing sandboxing techniques for font processing operations can provide additional protection layers, ensuring that even if exploitation occurs, the impact remains contained within isolated execution environments.