> 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 ...

***


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