CVE-2026-2704: Open Babel Buffer Overflow Vulnerability

CVE-2026-2704 Overview

A security vulnerability has been identified in Open Babel, a widely-used open-source chemistry toolbox designed for converting chemical file formats. The vulnerability exists in the OpenBabel::transform3d::DescribeAsString function within the file src/math/transform3d.cpp, which is part of the CIF (Crystallographic Information File) File Handler component. This out-of-bounds read vulnerability can be triggered remotely through specially crafted CIF files, potentially leading to information disclosure or application crashes.

Critical Impact

Remote attackers can exploit this out-of-bounds read vulnerability by supplying malicious CIF files to Open Babel, potentially causing denial of service or leaking sensitive memory contents.

Affected Products

• Open Babel up to version 3.1.1
• Applications integrating the Open Babel library for CIF file processing
• Systems processing untrusted CIF files through Open Babel

Discovery Timeline

• 2026-02-19 - CVE-2026-2704 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-2704

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the DescribeAsString function of the transform3d class, which handles mathematical transformations for 3D coordinate systems within crystallographic data. When processing malformed CIF files, the function fails to properly validate array boundaries before performing read operations, resulting in an out-of-bounds memory access condition.

The vulnerability can be exploited remotely since CIF files may be obtained from untrusted sources and processed by applications using the Open Babel library. While the immediate impact is limited to availability (denial of service through application crash), out-of-bounds read vulnerabilities can also potentially expose sensitive information from adjacent memory regions.

Root Cause

The root cause of this vulnerability is insufficient boundary checking in the OpenBabel::transform3d::DescribeAsString function located in src/math/transform3d.cpp. When processing transformation matrix data from CIF files, the function accesses array elements without verifying that the indices fall within the allocated buffer boundaries. This allows attackers to craft malicious CIF files that trigger reads beyond the intended memory region.

Attack Vector

The attack vector for this vulnerability is network-based, requiring user interaction to process a malicious file. An attacker can exploit this vulnerability by:

1. Creating a specially crafted CIF file containing malformed crystallographic transformation data
2. Distributing the malicious file through websites, email attachments, or shared repositories
3. Waiting for a victim to process the file using an application that leverages Open Babel's CIF parsing functionality
4. Upon processing, the out-of-bounds read is triggered in the DescribeAsString function, potentially causing an application crash or memory disclosure

A proof-of-concept CIF file demonstrating this vulnerability has been publicly disclosed. Technical details can be found in the GitHub Issue Discussion and the GitHub PoC Repository.

Detection Methods for CVE-2026-2704

Indicators of Compromise

• Unexpected crashes of applications using Open Babel when processing CIF files
• Abnormal memory access patterns or segmentation faults related to transform3d::DescribeAsString
• Presence of unusually structured or malformed CIF files in processing queues

Detection Strategies

• Monitor for application crashes or exceptions originating from the src/math/transform3d.cpp module
• Implement file integrity checks on incoming CIF files before processing
• Deploy memory sanitizers (AddressSanitizer, Valgrind) in development and testing environments to detect out-of-bounds access attempts
• Review application logs for repeated failures when processing specific CIF files

Monitoring Recommendations

• Enable verbose logging for Open Babel-based applications to capture CIF processing events
• Configure crash dump collection for applications using the Open Babel library
• Monitor for unusual volumes of CIF file submissions from untrusted sources
• Implement alerting on repeated CIF parsing failures from the same source

How to Mitigate CVE-2026-2704

Immediate Actions Required

• Audit systems to identify all applications using Open Babel for CIF file processing
• Implement input validation to reject malformed or suspicious CIF files before processing
• Consider sandboxing or isolating Open Babel processing components
• Monitor the GitHub Issue for vendor response and patch availability

Patch Information

As of the last update on 2026-02-19, the Open Babel project has been informed of this vulnerability through an issue report but has not yet responded. Users should monitor the official Open Babel repository for security patches. Additional vulnerability tracking information is available through VulDB.

Workarounds

• Restrict CIF file processing to files from trusted sources only
• Implement strict input validation for CIF files before passing them to Open Babel
• Run Open Babel processing in a sandboxed or containerized environment with limited privileges
• Consider alternative CIF parsing libraries until an official patch is released

In the absence of an official patch, the recommended defensive configuration involves limiting exposure to untrusted input:

# Configuration example
# Restrict file permissions for CIF processing directory
chmod 700 /path/to/cif/processing/
chown dedicated_user:dedicated_group /path/to/cif/processing/

# Run Open Babel in a restricted environment
# Using firejail as an example sandboxing solution
firejail --private --net=none obabel input.cif -O output.mol