What CVEs are caused by CWE-1336?

152 recorded CVEs are attributed to CWE-1336, including CVE-2024-23692, CVE-2024-4040, CVE-2026-33897. 2 are listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.

What are the consequences of CWE-1336?

Exploiting CWE-1336 can lead to: Execute Unauthorized Code or Commands.

Is CWE-1336 actively exploited?

Yes. 2 CWE-1336 vulnerabilities are in CISA's KEV catalog of actively exploited flaws, out of 152 recorded CVEs.

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Base weakness

Incomplete

CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine

Also known as: Server-Side Template Injection / SSTI, Client-Side Template Injection / CSTI

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.

Last updated May 1, 2026

152

Recorded CVEs

With this primary weakness

2

KEVs

In the CISA KEV catalog

Not rated

Likelihood of exploit

Per MITRE

Base

Abstraction

MITRE classification

Overview

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.

Real-world CVEs

152 recorded CVEs are caused by CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine), including 2 in CISA's KEV (Known Exploited Vulnerabilities) catalog. KEVs are shown first. 58 new CWE-1336 CVEs have been recorded so far in 2026 (53 in 2025).

Showing 12 of 152 recorded CWE-1336 CVEs. Track new ones as they are published and get AI-written analysis and fixes.

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Common consequences

What can happen when CWE-1336 is exploited.

Execute Unauthorized Code or Commands

Affects: Integrity

How it happens

When it is introduced

Typically introduced during these phases of the software lifecycle.

Architecture and Design

Implementation

Applies to

Languages

Java

PHP

Python

JavaScript

Interpreted

Technologies

AI/ML

Client Server

How to prevent it

Practical mitigations for CWE-1336, grouped by where in the lifecycle they apply.

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.

How to detect it

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

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

Terminology & mappings

Alternate terms

Server-Side Template Injection / SSTI: This term is used for injection into template engines being used by a server.
Client-Side Template Injection / CSTI: This term is used for injection into template engines being used by a client.

Frequently asked questions

Common questions about CWE-1336.

What is CWE-1336?: 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.
What CVEs are caused by CWE-1336?: 152 recorded CVEs are attributed to CWE-1336, including CVE-2024-23692, CVE-2024-4040, CVE-2026-33897. 2 are listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
How do you prevent CWE-1336?: 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.
How is CWE-1336 detected?: Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
What are the consequences of CWE-1336?: Exploiting CWE-1336 can lead to: Execute Unauthorized Code or Commands.
Is CWE-1336 actively exploited?: Yes. 2 CWE-1336 vulnerabilities are in CISA's KEV catalog of actively exploited flaws, out of 152 recorded CVEs.

References

Weakness data is sourced from the MITRE CWE catalog (v4.20). CVE associations are aggregated and kept current by RadicalNotion.AI.

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