CVE-2026-40527: radare2 Command Injection Vulnerability

CVE-2026-40527 Overview

CVE-2026-40527 is a command injection vulnerability affecting radare2, the popular open-source reverse engineering framework. The vulnerability exists in the afsv/afsvj command path where crafted ELF binaries can embed malicious r2 command sequences as DWARF DW_TAG_formal_parameter names. This allows attackers to achieve arbitrary shell command execution when security researchers or reverse engineers analyze a maliciously crafted binary.

Critical Impact

Attackers can achieve arbitrary shell command execution on systems where radare2 is used to analyze malicious ELF binaries, potentially compromising reverse engineering workstations and automated malware analysis pipelines.

Affected Products

• radare2 versions prior to commit bc5a890
• Any system using vulnerable radare2 for binary analysis
• Automated malware analysis pipelines using radare2

Discovery Timeline

• 2026-04-17 - CVE-2026-40527 published to NVD
• 2026-04-20 - Last updated in NVD database

Technical Details for CVE-2026-40527

Vulnerability Analysis

This vulnerability (CWE-78: Improper Neutralization of Special Elements used in an OS Command) enables command injection through a novel attack surface within DWARF debugging information. When radare2 parses ELF binaries containing DWARF debugging symbols, it extracts parameter names from DW_TAG_formal_parameter entries without proper sanitization.

The attack requires local access and some user interaction, as the victim must analyze the malicious binary using radare2's analysis commands. However, the impact is severe since successful exploitation grants the attacker arbitrary shell command execution with the privileges of the radare2 process.

Root Cause

The root cause lies in insufficient input sanitization when processing DWARF debugging information. The pfq command string interpolation mechanism accepts parameter names directly from the parsed DWARF data without validating or escaping special characters. This allows shell metacharacters embedded in DWARF parameter names to be interpreted as commands rather than literal strings.

Attack Vector

The attack vector requires an attacker to craft a malicious ELF binary with specially constructed DWARF debugging information. The malicious payload is embedded within the DW_TAG_formal_parameter name fields. When a security researcher or automated system analyzes this binary using radare2's aaa (analyze all) command followed by afsvj (analyze function signatures as JSON), the unsanitized parameter names are interpolated into shell command strings, resulting in arbitrary command execution.

The attack chain proceeds as follows: First, the attacker creates an ELF binary with DWARF information containing shell commands as parameter names. When the victim opens this binary in radare2 and runs analysis commands, the malicious parameter names are processed by the pfq command string construction, which fails to sanitize the input. The shell metacharacters are then interpreted, executing the attacker's payload.

Detection Methods for CVE-2026-40527

Indicators of Compromise

• Unusual process spawning from radare2 (r2) processes
• ELF binaries with abnormally long or suspicious DWARF parameter names containing shell metacharacters
• Unexpected network connections or file modifications during binary analysis sessions
• Presence of shell command syntax (;, |, $(), backticks) in DWARF debugging information

Detection Strategies

• Monitor process trees for child processes spawned by radare2 that shouldn't occur during normal analysis
• Implement DWARF structure validation to detect unusual or malicious parameter name patterns before analysis
• Use application sandboxing or containerization when analyzing untrusted binaries
• Deploy endpoint detection to identify command injection patterns in radare2 execution contexts

Monitoring Recommendations

• Enable comprehensive logging for all radare2 analysis sessions in automated pipelines
• Implement file integrity monitoring on systems used for reverse engineering
• Monitor for shell command execution patterns originating from binary analysis tools
• Consider network isolation for malware analysis environments

How to Mitigate CVE-2026-40527

Immediate Actions Required

• Update radare2 to a version containing commit bc5a890 or later
• Audit existing binary analysis workflows for exposure to untrusted binaries
• Implement sandboxing for radare2 analysis of untrusted files
• Review automated malware analysis pipelines that use radare2

Patch Information

The vulnerability has been addressed in radare2 commit bc5a89033db3ecb5b1f7bf681fc6ba4dcfc14683. Users should update to a version containing this fix. The patch implements proper sanitization of DWARF parameter names before they are used in command string construction. For more details, see the GitHub Radare2 Commit and GitHub Radare2 Pull Request. Additional technical information is available in the VulnCheck Advisory on Radare2.

Workarounds

• Analyze untrusted binaries in isolated environments (VMs, containers, or air-gapped systems)
• Use sandboxing tools like firejail or bubblewrap when running radare2 on untrusted files
• Avoid using the afsv and afsvj commands on untrusted binaries until patched
• Strip DWARF debugging information from untrusted binaries before analysis using strip --strip-debug

# Run radare2 in a sandboxed environment using firejail
firejail --private --net=none r2 suspicious_binary.elf

# Alternatively, strip DWARF info before analysis
strip --strip-debug suspicious_binary.elf