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Wagtail vulnerable to stored Cross-site Scripting attack via ModelAdmin views

High severity GitHub Reviewed Published Apr 3, 2023 in wagtail/wagtail • Updated Nov 19, 2024

Package

pip wagtail (pip)

Affected versions

>= 1.5, < 4.1.4
>= 4.2, < 4.2.2

Patched versions

4.1.4
4.2.2

Description

Impact

A stored cross-site scripting (XSS) vulnerability exists on ModelAdmin views within the Wagtail admin interface. A user with a limited-permission editor account for the Wagtail admin could potentially craft pages and documents that, when viewed by a user with higher privileges, could perform actions with that user's credentials. The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin, and only affects sites with ModelAdmin enabled.

  • For page, the vulnerability is in the "Choose a parent page" ModelAdmin view (ChooseParentView), available when managing pages via ModelAdmin.
  • For documents, the vulnerability is in the ModelAdmin Inspect view (InspectView) when displaying document fields.

Patches

Patched versions have been released as Wagtail 4.1.4 (for the LTS 4.1 branch) and Wagtail 4.2.2 (for the current 4.2 branch).

Workarounds

Site owners who are unable to upgrade to the new versions can disable or override the corresponding functionality.

ChooseParentView

For ChooseParentView:

  • Disable ModelAdmin for all page models.
  • Or provide a custom view via choose_parent_view_class, with the custom view overriding the get_form method.

One of those steps need to be applied for every ModelAdmin class hooked into Wagtail where the model is a Wagtail Page or sub-class. Here is an example of implementing the custom ChooseParentView with patched HTML escaping:

from django import forms
from django.utils.translation import gettext as _
from wagtail.contrib.modeladmin.views import ChooseParentView
from wagtail.contrib.modeladmin.forms import ParentChooserForm


class PatchedPageChoiceField(forms.ModelChoiceField):
    """PageChoiceField with plain-text breadcrumbs to patch stored XSS."""
    def label_from_instance(self, obj):
        bits = []
        for ancestor in (
            obj.get_ancestors(inclusive=True).exclude(depth=1).specific(defer=True)
        ):
            bits.append(ancestor.get_admin_display_title())
        return ' | '.join(bits)


class PatchedParentChooserForm(ParentChooserForm):
    """ParentChooserForm with custom parent_page to patch stored XSS."""
    parent_page = PatchedPageChoiceField(
        label=_("Parent page"),
        required=True,
        empty_label=None,
        queryset=Page.objects.none(),
        widget=forms.RadioSelect(),
    )


class PatchedChooseParentView(ChooseParentView):
    """ChooseParentView with custom get_form patch stored XSS."""
    def get_form(self, request):
        parents = self.permission_helper.get_valid_parent_pages(request.user)
        return PatchedParentChooserForm(parents, request.POST or None)

InspectView

For InspectView:

One of those steps need to be applied for every ModelAdmin class hooked into Wagtail where inspect_view_enabled=True. Here is an example of implementing the custom InspectView with patched HTML escaping:

from django.template.defaultfilters import filesizeformat
from django.utils.html import format_html
from wagtail.contrib.modeladmin.views import InspectView


class PatchedInspectView(InspectView):
    """InspectView with override to patch stored XSS vulnerability."""
    def get_document_field_display(self, field_name, field):
        """Render a link to a document"""
        document = getattr(self.instance, field_name)
        if document:
            return format_html(
                '<a href="{}">{} <span class="meta">({}, {})</span></a>',
                document.url,
                document.title,
                document.file_extension.upper(),
                filesizeformat(document.file.size),
            )
        return self.model_admin.get_empty_value_display(field_name)

References

@gasman gasman published to wagtail/wagtail Apr 3, 2023
Published by the National Vulnerability Database Apr 3, 2023
Published to the GitHub Advisory Database Apr 3, 2023
Reviewed Apr 3, 2023
Last updated Nov 19, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements Present
Privileges Required Low
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

0.101%
(43rd percentile)

Weaknesses

CVE ID

CVE-2023-28836

GHSA ID

GHSA-5286-f2rf-35c2

Source code

Credits

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