CVE-2023-46045: Graphviz Buffer Overflow Vulnerability

CVE-2023-46045 Overview

CVE-2023-46045 is an out-of-bounds read vulnerability affecting Graphviz, the popular open-source graph visualization software. The vulnerability exists in Graphviz versions 2.36.0 through 9.x before 10.0.1 and can be triggered via a crafted config6a file. While the config6a file is typically owned by root which may limit practical exploitability in some environments, successful exploitation could lead to information disclosure, denial of service, or potentially arbitrary code execution.

Critical Impact

This out-of-bounds read vulnerability in Graphviz can potentially be leveraged for code execution when processing maliciously crafted configuration files.

Affected Products

• Graphviz versions 2.36.0 through 9.x
• Graphviz versions prior to 10.0.1
• Any system utilizing vulnerable Graphviz installations for graph processing

Discovery Timeline

• 2024-02-02 - CVE-2023-46045 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2023-46045

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), a memory corruption vulnerability that occurs when software reads data past the end of an allocated buffer. In the context of Graphviz, the vulnerability is triggered when the application processes a specially crafted config6a configuration file.

When Graphviz parses the malicious configuration file, it fails to properly validate input boundaries, causing the application to read memory beyond the intended buffer limits. This can expose sensitive information stored in adjacent memory regions or cause the application to crash. According to references available on Packet Storm Security, the vulnerability has been associated with buffer overflow conditions that could potentially lead to code execution.

The attack requires local access and user interaction—specifically, a user must process a malicious configuration file. While the config6a file is typically owned by root, which may limit exploitation scenarios, environments where users have elevated privileges or misconfigured file permissions remain at risk.

Root Cause

The root cause of CVE-2023-46045 lies in insufficient bounds checking during the parsing of the config6a configuration file in Graphviz. The vulnerable code fails to validate that array indices and memory access operations remain within allocated buffer boundaries. This oversight allows attackers to craft configuration files that trigger memory reads beyond intended buffer limits, potentially exposing sensitive data or corrupting program state.

Attack Vector

The attack vector for this vulnerability is local, requiring an attacker to either have local system access or convince a user to process a malicious file. The exploitation scenario involves:

1. An attacker crafts a malicious config6a file with specially constructed data designed to trigger the out-of-bounds read
2. The crafted file is placed in a location where Graphviz will process it, or a user is tricked into processing it
3. When Graphviz parses the malicious configuration, the out-of-bounds read is triggered
4. Depending on memory layout, this can lead to information disclosure, crash, or potentially code execution

The vulnerability mechanism involves improper boundary validation when processing configuration file contents. For detailed technical analysis, refer to the GitLab Issue #2441 or the OSS-Security discussion.

Detection Methods for CVE-2023-46045

Indicators of Compromise

• Unexpected crashes or segmentation faults in Graphviz processes
• Unusual memory access patterns or errors in system logs related to Graphviz execution
• Presence of suspicious or modified config6a files with abnormal content
• Graphviz processes attempting to access memory regions outside expected boundaries

Detection Strategies

• Deploy memory corruption detection tools such as AddressSanitizer (ASan) in development and testing environments to identify out-of-bounds access attempts
• Implement file integrity monitoring on Graphviz configuration files, particularly config6a, to detect unauthorized modifications
• Monitor for unusual Graphviz process behavior including unexpected crashes or abnormal resource consumption
• Utilize endpoint detection and response (EDR) solutions to detect exploitation attempts targeting memory vulnerabilities

Monitoring Recommendations

• Enable detailed logging for Graphviz operations to capture file access and processing events
• Implement alerting for Graphviz process crashes or abnormal terminations
• Monitor file system changes to configuration directories used by Graphviz
• Review system logs for memory-related errors associated with Graphviz processes

How to Mitigate CVE-2023-46045

Immediate Actions Required

• Upgrade Graphviz to version 10.0.1 or later immediately to remediate the vulnerability
• Audit existing Graphviz installations across your environment to identify vulnerable versions
• Restrict access to Graphviz configuration files, ensuring config6a maintains appropriate root ownership
• Consider temporarily disabling or isolating systems running vulnerable Graphviz versions until patching is complete

Patch Information

The vulnerability has been addressed in Graphviz version 10.0.1. Organizations should upgrade to this version or later to fully remediate CVE-2023-46045. The fix implements proper bounds checking when parsing configuration files to prevent out-of-bounds memory reads.

For detailed information about the vulnerability and fix, refer to the GitLab Issue #2441 and the Full Disclosure Announcement.

Workarounds

• Ensure config6a files maintain strict root ownership and restrictive permissions (mode 0644 or more restrictive)
• Implement application sandboxing or containerization for Graphviz processes to limit potential impact
• Restrict which users can invoke Graphviz utilities in multi-user environments
• Consider using application-level firewalls or security policies to prevent processing of untrusted configuration files

# Configuration example: Restrict config6a file permissions
# Ensure root ownership and restricted read access
sudo chown root:root /usr/lib/graphviz/config6a
sudo chmod 644 /usr/lib/graphviz/config6a

# Verify Graphviz version (upgrade if below 10.0.1)
dot -V