> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/appsec-rules/iac-security/compute/appsec-docker-11.md).

# Docker From alias is not unique for multistage builds misconfiguration detected in code

## Rule Details

|                        |                                |
| ---------------------- | ------------------------------ |
| Cortex AppSec Rule ID  | APPSEC\_DOCKER\_11             |
| Category - Subcategory | Compute - Startup Script Leaks |
| Provider               | OTHER                          |
| Severity               | LOW                            |
| Framework              | DOCKER                         |

## Impact

This rule detects whether each FROM instruction in a Dockerfile uses a unique alias when building multistage images. Aliases help to identify stages, making Dockerfiles more readable and maintainable. Enforcing unique aliases ensures clarity, prevents conflicts and avoids any unintentional overwriting of stages.

## How to Fix

To mitigate this issue, ensure that each `FROM` instruction in your multistage Dockerfile uses a unique alias.

## Example: \[source,go]

FROM node:14 as builder ...

* FROM node:14 as builder # Duplicate alias
* FROM node:14 as builder\_2 # Unique alias ...

***


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://cortex-docs.paloaltonetworks.com/appsec-rules/iac-security/compute/appsec-docker-11.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.