CVE-2026-40517: radare2 PDB Parser RCE Vulnerability

CVE-2026-40517 Overview

CVE-2026-40517 is a command injection vulnerability affecting radare2 versions prior to 6.1.4. The flaw exists in the PDB parser's print_gvars() function, which fails to properly sanitize symbol names when processing PDB (Program Database) files. Attackers can craft malicious PDB files containing newline characters in symbol names to inject arbitrary radare2 commands, ultimately enabling arbitrary OS command execution when a user analyzes the malicious file.

Critical Impact

Successful exploitation allows attackers to execute arbitrary operating system commands on the victim's machine when they analyze a malicious PDB file using radare2's idp command.

Affected Products

• radare2 versions prior to 6.1.4

Discovery Timeline

• April 22, 2026 - CVE CVE-2026-40517 published to NVD
• April 22, 2026 - Last updated in NVD database

Technical Details for CVE-2026-40517

Vulnerability Analysis

This command injection vulnerability (CWE-78) stems from improper input validation in radare2's PDB file parser. The print_gvars() function processes symbol names from PDB files and uses them in flag rename commands without adequate sanitization. When symbol names contain newline characters or other control sequences, these characters break out of the intended command context, allowing injection of additional radare2 commands.

The attack requires local access and user interaction—specifically, a user must open and analyze a maliciously crafted PDB file using the idp command. Once triggered, the attacker can leverage radare2's shell execution operator to escalate from radare2 command injection to full OS command execution.

Root Cause

The root cause is insufficient input sanitization in the print_gvars() function when interpolating symbol names into radare2's internal command string. PDB files store debug symbol information, including variable and function names. The parser trusts these names without validating or escaping special characters such as newlines, which can be used to terminate the current command and inject new ones.

Attack Vector

The attack vector is local, requiring an attacker to deliver a malicious PDB file to the victim. This could be accomplished through various social engineering methods such as including the malicious file in a software package, attaching it to an email, or hosting it on a code repository. When the victim uses radare2 to analyze the binary and loads the associated PDB file with the idp command, the injected commands execute automatically.

The exploitation flow involves:

1. Crafting a PDB file with symbol names containing embedded newline characters
2. Injecting radare2 commands after the newline that leverage the shell execution operator
3. Distributing the malicious PDB file to victims
4. Command execution occurs when victims analyze the file with radare2's idp command

For detailed technical analysis and proof-of-concept information, refer to the California Blog 0-Day Discovery article and the GitHub Issue #25730.

Detection Methods for CVE-2026-40517

Indicators of Compromise

• PDB files containing newline characters (\n) or carriage returns within symbol names
• Unusual radare2 command sequences in shell history or process logs
• Unexpected child processes spawned from radare2 analysis sessions
• PDB files with symbol names containing radare2 shell operator syntax

Detection Strategies

• Implement file integrity monitoring for PDB files in development environments
• Monitor for unusual process spawning patterns from radare2 processes
• Deploy endpoint detection rules to identify command injection patterns in reverse engineering tools
• Scan incoming PDB files for suspicious embedded characters before analysis

Monitoring Recommendations

• Enable verbose logging in radare2 sessions when analyzing untrusted files
• Monitor network connections initiated by radare2 processes for potential data exfiltration
• Implement sandboxed environments for analyzing untrusted binary and debug files
• Track file access patterns for PDB files from untrusted sources

How to Mitigate CVE-2026-40517

Immediate Actions Required

• Upgrade radare2 to version 6.1.4 or later immediately
• Avoid analyzing PDB files from untrusted sources until patched
• Run radare2 in sandboxed or containerized environments when analyzing unknown files
• Review any systems where untrusted PDB files may have been analyzed recently

Patch Information

The vulnerability has been addressed in radare2 version 6.1.4. The fix involves proper sanitization of symbol names before interpolation into internal commands. For details on the patch implementation, see GitHub Pull Request #25731. Users should update to the latest version using their package manager or by building from source.

Additional advisory information is available from VulnCheck Radare2 Command Injection Advisory.

Workarounds

• Analyze untrusted PDB files in isolated virtual machines or containers with no network access
• Use alternative debugging tools for analyzing PDB files from untrusted sources until upgrade is possible
• Implement strict file source verification policies for all debug symbol files
• Consider disabling PDB parsing functionality if not required for your workflow

# Configuration example
# Upgrade radare2 to patched version
# Using package manager (example for systems with radare2 package)
sudo apt update && sudo apt install radare2

# Or build from source with latest patches
git clone https://github.com/radareorg/radare2
cd radare2
git checkout 6.1.4
sys/install.sh

# Verify installed version
r2 -v