GHSA-56v6-2fhr-wxgq: XSS
Impact What kind of vulnerability is it? Who is impacted?
It has two related instances that share the same root cause: a user-controlled model field is assigned verbatim to a form field's helptext, which is rendered with Django's |safe filter (renderfield.html), bypassing auto-escaping.
In both cases the script executes in the browser of any user who opens an affected create or edit form, including administrators and superusers. Because the payload runs in the victim's authenticated session, it can lead to actions performed as the victim, session/token theft, and further privilege escalation. Exploitation requires the victim to open an affected form.
Relationship description
A user who holds the add/change permission for Relationships (extras.addrelationship / extras.changerelationship) can set a Relationship's description to an HTML/JavaScript payload. That description is used as the help text of the relationship's form field and is rendered on the create/edit page of every object type the relationship applies to.
Module Family name
A user who holds the add/change permission for Module Families (dcim.addmodulefamily / dcim.changemodulefamily) can put a payload in a Module Family name, which is interpolated into the modulefamily field's help text on the Module "Install module" form for any module bay assigned to that family.
Patches Has the problem been patched? What versions should users upgrade to?
Fixes are available in Nautobot v2.4.37+ & v3.1.8+
Note: The underlying weakness exists in earlier EOL versions of Nautobot (v1.x). Users on those older EOL versions are highly encouraged to upgrade to a supported version.
Workarounds Is there a way for users to fix or remediate the vulnerability without upgrading?
There is no configuration-only fix. To remediate without upgrading:
- Restrict the extras.addrelationship / extras.changerelationship and dcim.addmodulefamily / dcim.changemodulefamily permissions to fully trusted administrators only. - Audit existing Relationship description values and Module Family name values for embedded HTML / <script> content and remove any payloads.
Note that limiting who can open create/edit forms does not fully mitigate the issue, since the payload targets any user (including admins) who opens an affected form.
Credit
Credit for this discovery goes to Habibullo Izzatilloyev.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
pip/nautobotto a version that resolves this vulnerability.Fixed in 3.1.8 - Upgrade
Upgrade
pip/nautobotto a version that resolves this vulnerability.Fixed in 2.4.37 - Upgrade
Upgrade
Nautobotto a version that resolves this vulnerability.Fixed in 2.4.37 - Upgrade
Upgrade
Nautobotto a version that resolves this vulnerability.Fixed in 3.1.8 - Configuration
Restrict the Relationship and Module Family add/change permissions to fully trusted administrators only.
Nautobot permissions extras.add_relationship, extras.change_relationship, dcim.add_modulefamily, dcim.change_modulefamily = fully trusted administrators only - Operational
Audit existing Relationship description values and Module Family name values for embedded HTML or <script> content, and remove any payloads.
Event History
Frequently Asked Questions
Who can introduce a malicious payload?
A user with add or change permission for Relationships can place a payload in a Relationship description. The advisory also identifies a related Module Family name case, but the provided data does not specify the required permissions for that instance.
Which users are at risk of triggering the payload?
Any user who opens an affected create or edit form can execute the payload, including administrators and superusers. For Relationship descriptions, this includes create or edit pages for every object type to which the Relationship applies.
What must occur for exploitation to succeed?
The attacker must first be able to store HTML or JavaScript in an affected user-controlled field. A victim must then open an affected form; the payload executes in that victim's authenticated browser session.
What could an attacker do after a victim triggers the payload?
The payload may perform actions as the authenticated victim, steal session or token material, and support further privilege escalation. The impact depends on the permissions held by the user who opens the affected form.