starred/netbox
1
0
Fork 0
mirror of https://github.com/netbox-community/netbox.git synced 2026-01-11 21:10:29 +01:00
Code Issues 273 Packages Projects Releases 10 Wiki Activity

HTML injection in Custom Field Choice description field allows content spoofing #11472

New Issue
Closed
opened 2025-12-29 21:45:41 +01:00 by adam · 1 comment
adam commented 2025-12-29 21:45:41 +01:00
Owner
Copy Link

Originally created by @jnovinger on GitHub (Aug 11, 2025).

Originally assigned to: @jeremystretch on GitHub.

Deployment Type

Self-hosted

NetBox Version

v4.3.5

Python Version

3.10

Steps to Reproduce

  1. Log in to NetBox with appropriate permissions
  2. Navigate to Customization > Custom Field Choices
  3. Click Add to create a new custom field choice
  4. Fill in the required Name field (e.g., "TEST_CHOICE")
  5. In the Description field, enter the following HTML payload: 
    "><a href=https://example.com>CLICK ME</a>
  6. Complete any other required fields and click Create
  7. Navigate back to the Custom Field Choices list
  8. Observe the description field for the newly created choice

Note: We should check other description fields for this behavior.

Expected Behavior

The HTML payload should be escaped and displayed as plain text. Special characters like <, >, and quotes should be encoded to prevent HTML interpretation.

Observed Behavior

The HTML payload is rendered as actual HTML in the interface. The injected anchor tag <a href=https://example.com>CLICK ME</a> appears as a clickable link, allowing potential content spoofing and social engineering attacks.

Originally created by @jnovinger on GitHub (Aug 11, 2025). Originally assigned to: @jeremystretch on GitHub. ### Deployment Type Self-hosted ### NetBox Version v4.3.5 ### Python Version 3.10 ### Steps to Reproduce 1. Log in to NetBox with appropriate permissions 2. Navigate to **Customization > Custom Field Choices** 3. Click **Add** to create a new custom field choice 4. Fill in the required **Name** field (e.g., "TEST_CHOICE") 5. In the **Description** field, enter the following HTML payload: ``` "><a href=https://example.com>CLICK ME</a> ``` 6. Complete any other required fields and click **Create** 7. Navigate back to the Custom Field Choices list 8. Observe the description field for the newly created choice Note: We should check other description fields for this behavior. ### Expected Behavior The HTML payload should be escaped and displayed as plain text. Special characters like `<`, `>`, and quotes should be encoded to prevent HTML interpretation. ### Observed Behavior The HTML payload is rendered as actual HTML in the interface. The injected anchor tag `<a href=https://example.com>CLICK ME</a>` appears as a clickable link, allowing potential content spoofing and social engineering attacks.
adam added the type: bugstatus: acceptedseverity: low labels 2025-12-29 21:45:41 +01:00
adam closed this issue 2025-12-29 21:45:41 +01:00
adam commented 2025-12-29 21:45:42 +01:00
Author
Owner
Copy Link

@jeremystretch commented on GitHub (Aug 20, 2025):

This is actually valid behavior because we support Markdown rendering for custom field descriptions, and the HTML given is permitted because it can be created using Markdown. The provided HTML is sanitized. For example, <a href="#" onclick="alert('foo')">click me</a> will render a link but omit the potentially dangerous onclick attribute.

I'm going to close this out as I don't believe any changes are needed.

@jeremystretch commented on GitHub (Aug 20, 2025): This is actually valid behavior because we support Markdown rendering for custom field descriptions, and the HTML given is permitted because it can be created using Markdown. The provided HTML is sanitized. For example, `<a href="#" onclick="alert('foo')">click me</a>` will render a link but omit the potentially dangerous `onclick` attribute. I'm going to close this out as I don't believe any changes are needed.
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
beta
breaking change
complexity: high
complexity: low
complexity: medium
needs milestone
netbox
pending closure
plugin candidate
pull-request
Mirrored from GitHub Pull Request
 severity: high
severity: low
severity: medium
status: accepted
status: backlog
status: blocked
status: duplicate
status: needs owner
status: needs triage
status: revisions needed
status: under review
topic: GraphQL
topic: Internationalization
topic: OpenAPI
topic: UI/UX
topic: cabling
topic: event rules
topic: htmx navigation
topic: industrialization
topic: migrations
topic: plugins
topic: scripts
topic: templating
topic: testing
type: bug
type: deprecation
type: documentation
type: feature
type: housekeeping
type: translation
No Label severity: low status: accepted type: bug
Milestone
No items
No Milestone
Projects
Clear projects
No project
Assignees
Clear assignees
adam
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: starred/netbox#11472
Delete Branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?