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GHSA-v7qw-hx66-4w9x

HighCVSS 8.7 / 10
Published May 7, 2026·Last modified May 7, 2026
Affected Components(0)

No affected components available

Description

Summary

An authenticated user who can create or edit ObjectAlias objects can store arbitrary HTML/JavaScript in an alias name. That payload is later rendered unescaped in DataFlow table views, causing a stored XSS when another user views the affected page.

Details

The issue is caused by unsafe HTML generation in the plugin’s custom table column renderer.

Relevant code on main (bf96eac, same commit as origin/main at the time of review):

  • netbox_data_flows/models/objectaliases.py
    • ObjectAlias.name is user-controlled (CharField)
    • ObjectAlias.__str__() returns self.name directly
  • netbox_data_flows/tables/dataflows.py
    • DataFlowTable.sources and DataFlowTable.destinations use ObjectAliasListColumn
  • netbox_data_flows/tables/columns.py
    • ObjectAliasListColumn.render() calls object_list_to_string(value.all(), linkify=True)
  • netbox_data_flows/utils/helpers.py
    • object_list_to_string() builds raw anchor tags with: 
      mark_safe(separator.join(f'<a href="{o.get_absolute_url()}">{o}</a>' for o in objects))

The alias text ({o}) is inserted into HTML without escaping, then the whole string is marked safe. Because ObjectAlias.__str__() returns the user-supplied name, HTML/JS in the alias name is executed in the victim’s browser.

This affects any page rendering DataFlowTable, including at least:

  • the main Data Flow list page
  • model tabs that reuse DataFlowTable

PoC

Environment:

  • NetBox with netbox-data-flows installed
  • No special plugin configuration required

Steps:

  1. Log in as a user with permission to create or edit ObjectAlias and DataFlow.
  2. Create a new ObjectAlias with the following name: 
    <img src=x onerror=alert(document.domain)>
  3. Create or edit a DataFlow so this alias is present in either sources or destinations.
  4. Log in as another user and open the Data Flow list page in the plugin UI.
  5. The JavaScript executes when the table renders the alias list.

A simple path to trigger is the Data Flow list page. Any other page that renders DataFlowTable should also be tested.

Impact

This is a stored cross-site scripting vulnerability.

Impacted users:

  • any authenticated user who can view a page rendering the affected DataFlow table
  • especially higher-privileged NetBox users, because an attacker with lower privileges may target them by planting a malicious alias name

Possible impact:

  • session theft
  • execution of privileged actions in the victim’s session
  • exfiltration of data visible to the victim in NetBox
Risk Scores
Base Score
8.7

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data.

Threat Intelligence
8.0

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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