Saku0512/CVE-2026-40176-poc

GitHubRepository PoCExploit

PoC files

4 files

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GitHub
Analysisdeepseek-v4-pro:cloud ·

Technical assessment

The artifact is a Proof of Concept exploit for CVE-2026-40176, a command injection vulnerability in Composer's Perforce driver. It includes a PHP script (poc.php) that reproduces the vulnerable command generation logic and executes a malicious command via system(), creating a file to confirm code execution.

Backdoor review

No backdoor observed in reviewed code

The repository is a straightforward Proof of Concept for CVE-2026-40176. It contains documentation and a PHP script that reproduces the reported command injection vulnerability. The script constructs and executes a command using the same unsanitized concatenation pattern described in the CVE. The payload demonstrated is the benign 'touch /tmp/pwned_rce_confirmed' command, which is consistent with the educational purpose stated in the disclaimers. No concealed, deceptive, or unrelated harmful behavior was observed.

ClassificationExploit
Model confidence98%
AuthenticationNot required
LanguagesPHPMarkdown
Target softwareComposer
Attack typesOS Command Injection
Evidence & reasoningClassification basis · observed behavior · safety review
Technical evidence

Classification basis and observed behavior

Classification basis

The artifact contains executable code (poc.php) that actively exercises the vulnerability by generating and executing a malicious command via system(), which is the defining characteristic of an exploit. The README files explicitly describe it as a Proof of Concept and provide instructions to run the script to confirm RCE.

poc.php:69-75README.en.md:1-4

Requirements

  • PHP must be installed to run the PoC script.README.en.md:41-42
  • The victim must run the PoC script (poc.php) or a Composer command on a project containing the malicious composer.json.README.en.md:66-72

Observed behavior

  • The poc.php script constructs a shell command by concatenating attacker-controlled input (a malicious port string containing '; touch /tmp/pwned_rce_confirmed #') without escaping.poc.php:40-50
  • The script executes the constructed command using system(), which passes it to the system shell, causing the injected 'touch' command to run.poc.php:69-75
  • The script checks for the existence of '/tmp/pwned_rce_confirmed' to confirm successful command execution, then cleans up the file.poc.php:77-82
Safety-review evidence

Behaviors behind the backdoor verdict

Observables

Command Execution
system($fullCommand);The PoC script executes the generated command, which includes the injected 'touch /tmp/pwned_rce_confirmed' payload. This is the expected behavior for demonstrating the vulnerability.poc.php:75
Payload
touch /tmp/pwned_rce_confirmedThe injected command is a benign file creation used to confirm successful exploitation. It is documented in the README files and hardcoded in both composer.json and poc.php.composer.json:6poc.php:59
Review boundaries

What the analysis did not establish

  • The evidence does not include the actual vulnerable Composer source code; the PoC reproduces the vulnerable logic in a standalone class.
  • The PoC uses system() directly, while the real Composer vulnerability involves ProcessExecutor::execute(), but the shell injection mechanism is analogous.
Model interpretation

This review is limited to the supplied PoC code and context. It does not assert that the code works or is safe to execute.

Linked vulnerabilities

1