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CWE-1336

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CWE-1336

Improper Neutralization of Special Elements Used in a Template Engine

Base
Incomplete

Description

The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.

{"xhtml:p":["Many web applications use template engines that allow developers to insert externally-influenced values into free text or messages in order to generate a full web page, document, message, etc. Such engines include Twig, Jinja2, Pug, Java Server Pages, FreeMarker, Velocity, ColdFusion, Smarty, and many others - including PHP itself. Some CMS (Content Management Systems) also use templates.","Template engines often have their own custom command or expression language. If an attacker can influence input into a template before it is processed, then the attacker can invoke arbitrary expressions, i.e. perform injection attacks. For example, in some template languages, an attacker could inject the expression \"{{7*7}}\" and determine if the output returns \"49\" instead. The syntax varies depending on the language.","In some cases, XSS-style attacks can work, which can obscure the root cause if the developer does not closely investigate the root cause of the error.","Template engines can be used on the server or client, so both \"sides\" could be affected by injection. The mechanisms of attack or the affected technologies might be different, but the mistake is fundamentally the same."]}

Common Consequences

Scope

Integrity

Impact

Execute Unauthorized Code or Commands

Potential Mitigations

Architecture and Design

Choose a template engine that offers a sandbox or restricted mode, or at least limits the power of any available expressions, function calls, or commands.

Implementation

Use the template engine's sandbox or restricted mode, if available.

CVE-2024-34359

Chain: Python bindings for LLM library do not use a sandboxed environment when parsing a template and constructing a prompt, allowing jinja2 Server Side Template Injection and code execution - one variant of a "prompt injection" attack.

CVE-2017-16783

server-side template injection in content management server

CVE-2020-9437

authentication / identity management product has client-side template injection

CVE-2020-12790

Server-Side Template Injection using a Twig template

CVE-2021-21244

devops platform allows SSTI

CVE-2020-4027

bypass of Server-Side Template Injection protection mechanism with macros in Velocity templates

CVE-2020-26282

web browser proxy server allows Java EL expressions from Server-Side Template Injection

CVE-2020-1961

SSTI involving mail templates and JEXL expressions

CVE-2019-19999

product does not use a "safe" setting for a FreeMarker configuration, allowing SSTI

CVE-2018-20465

product allows read of sensitive database username/password variables using server-side template injection

Applicable Platforms

Java
PHP
Python
JavaScript
Interpreted

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