Summary
The MCP server webasyst-mcp is vulnerable to command injection due to unsafe use of execSync with user-controlled input in the compile_mo MCP tool.
Vulnerable Code
Details
Based on the reviewed code path, the issue involves app_id, locale, po, mo. The reviewed code path reaches a shell-string execution sink in a way that is inconsistent with the tool's documented scope.
The reviewed code does not use a stronger boundary such as argv-based process execution, a destination allowlist, parsed SQL enforcement, or another control that would make the execution step consistent with the tool's documented scope.
compile_mo
Confirmed user-controlled or user-selected values in the reviewed path: app_id, locale, po, mo.
Relevant code:
Tool handler and argument flow:
1300: // ========= Localization & release helpers =========
1301: async function generatePoTemplateTool({ app_id, locale = 'ru_RU' }) {
1302: const rootPath = await findWebasystRoot();
1303: const poDir = path.join(rootPath, 'wa-apps', app_id, 'locale', locale, 'LC_MESSAGES');
1304: await ensureDir(poDir);
1312:
1313: async function compileMoTool({ app_id, locale = 'ru_RU' }) {
1314: const rootPath = await findWebasystRoot();
1315: const poPath = path.join(rootPath, 'wa-apps', app_id, 'locale', locale, 'LC_MESSAGES', `${app_id}.po`);
1316: const moPath = path.join(rootPath, 'wa-apps', app_id, 'locale', locale, 'LC_MESSAGES', `${app_id}.mo`);Command / request / execution flow:
1304: await ensureDir(poDir);
1305: const poPath = path.join(poDir, `${app_id}.po`);
1306: if (!(await fileExists(poPath))) {
1307: const header = `msgid ""\nmsgstr ""\n"Project-Id-Version: ${app_id}\\n"\n"Content-Type: text/plain; charset=UTF-8\\n"\n"Language: ${locale}\\n"\n\n`;
1308: await fs.writeFile(poPath, header);
1309: }
1310: return { content: [{ type: 'text', text: `PO шаблон подготовлен: ${poPath}` }] };
1318: try {
1319: execSync(`msgfmt "${poPath}" -o "${moPath}"`);
1320: return { content: [{ type: 'text', text: `MO скомпилирован: ${moPath}` }] };
1321: } catch (e) {
1322: throw new Error('Не удалось выполнить msgfmt. Установите gettext.');Impact
Inject additional shell syntax and execute unintended commands in the server environment.
Recommendation
- Avoid passing user-controlled data through shell-string execution.
- Use
spawn, execFile, or equivalent argv-based execution APIs so arguments are not re-parsed by a shell.
- Apply strict allowlists or structural validation to high-risk fields before they reach the sensitive sink.
Summary
The MCP server
webasyst-mcpis vulnerable to command injection due to unsafe use ofexecSyncwith user-controlled input in thecompile_moMCP tool.Vulnerable Code
Details
Based on the reviewed code path, the issue involves
app_id,locale,po,mo. The reviewed code path reaches a shell-string execution sink in a way that is inconsistent with the tool's documented scope.The reviewed code does not use a stronger boundary such as argv-based process execution, a destination allowlist, parsed SQL enforcement, or another control that would make the execution step consistent with the tool's documented scope.
compile_moConfirmed user-controlled or user-selected values in the reviewed path:
app_id,locale,po,mo.Relevant code:
Tool handler and argument flow:
Command / request / execution flow:
Impact
Inject additional shell syntax and execute unintended commands in the server environment.
Recommendation
spawn,execFile, or equivalent argv-based execution APIs so arguments are not re-parsed by a shell.