GHSA-F2P5-J6FG-5CXF

Vulnerability from github – Published: 2026-08-20 18:40 – Updated: 2026-08-20 18:40
VLAI
Summary
Wagtail: Denial of service via unbounded filter specs in the image preview
Details

Impact

An authenticated admin user can trigger expensive rendition processing with purposefully crafted filter specs resulting in potentially service degradation.

The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin.

Patches

Patched versions have been released as Wagtail 7.0.8, 7.3.3, 7.4.2.

Workarounds

For sites that cannot easily upgrade to a current supported version, the vulnerability can be patched by adding the following code to urls.py URL pattern declarations to override the vulnerable view.

from django.core.exceptions import PermissionDenied
from django.http import HttpResponseBadRequest
from django.shortcuts import get_object_or_404
from django.urls import path
from wagtail.admin import urls as wagtailadmin_urls
from wagtail.images.exceptions import InvalidFilterSpecError
from wagtail.images.permissions import permission_policy
from wagtail.images.views import preview


def patched_preview(request, image_id, filter_spec):
    image = get_object_or_404(get_image_model(), id=image_id)

    if not permission_policy.user_has_permission_for_instance(request.user, "change", image):
        raise PermissionDenied

    try:
        filter_obj = Filter(spec=filter_spec)
    except InvalidFilterSpecError:
        return HttpResponseBadRequest("Invalid filter spec", content_type="text/plain")

    allowed = {"original", "width", "height", "min", "max", "fill"}
    if any(operation.method not in allowed for operation in filter_obj.operations):
        return HttpResponseBadRequest("Invalid filter spec", content_type="text/plain")

    return preview(request, image_id, filter_spec)


urlpatterns = [
    # Example where the CMS admin is at /admin/.
    # Add this before the Wagtail admin URLs registration, with the same sub-path.
    path("admin/images/<int:image_id>/preview/<str:filter_spec>/", patched_preview)
    path("admin/", include(wagtailadmin_urls)),
]

Acknowledgements

Many thanks to @0x1saac for reporting this issue.

For more information

If you have any questions or comments about this advisory:

Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "wagtail"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "wagtail"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.1"
            },
            {
              "fixed": "7.3.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "wagtail"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.4"
            },
            {
              "fixed": "7.4.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54260"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-20T18:40:13Z",
    "nvd_published_at": "2026-07-01T22:16:49Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nAn authenticated admin user can trigger expensive rendition processing with purposefully crafted filter specs resulting in potentially service degradation.\n\nThe vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin.\n\n### Patches\nPatched versions have been released as Wagtail 7.0.8, 7.3.3, 7.4.2.\n\n### Workarounds\nFor sites that cannot easily upgrade to a current supported version, the vulnerability can be patched by adding the following code to `urls.py` URL pattern declarations to override the vulnerable view.\n\n```python\nfrom django.core.exceptions import PermissionDenied\nfrom django.http import HttpResponseBadRequest\nfrom django.shortcuts import get_object_or_404\nfrom django.urls import path\nfrom wagtail.admin import urls as wagtailadmin_urls\nfrom wagtail.images.exceptions import InvalidFilterSpecError\nfrom wagtail.images.permissions import permission_policy\nfrom wagtail.images.views import preview\n\n\ndef patched_preview(request, image_id, filter_spec):\n    image = get_object_or_404(get_image_model(), id=image_id)\n\n    if not permission_policy.user_has_permission_for_instance(request.user, \"change\", image):\n        raise PermissionDenied\n\n    try:\n        filter_obj = Filter(spec=filter_spec)\n    except InvalidFilterSpecError:\n        return HttpResponseBadRequest(\"Invalid filter spec\", content_type=\"text/plain\")\n\n    allowed = {\"original\", \"width\", \"height\", \"min\", \"max\", \"fill\"}\n    if any(operation.method not in allowed for operation in filter_obj.operations):\n        return HttpResponseBadRequest(\"Invalid filter spec\", content_type=\"text/plain\")\n\n    return preview(request, image_id, filter_spec)\n\n\nurlpatterns = [\n    # Example where the CMS admin is at /admin/.\n    # Add this before the Wagtail admin URLs registration, with the same sub-path.\n    path(\"admin/images/\u003cint:image_id\u003e/preview/\u003cstr:filter_spec\u003e/\", patched_preview)\n    path(\"admin/\", include(wagtailadmin_urls)),\n]\n```\n\n### Acknowledgements\nMany thanks to @0x1saac for reporting this issue.\n\n\n### For more information\nIf you have any questions or comments about this advisory:\n\n* Visit Wagtail\u0027s [support channels](https://docs.wagtail.org/en/stable/support.html)\n* Email us at [security@wagtail.org](mailto:security@wagtail.org) (view our [security policy](https://github.com/wagtail/wagtail/security/policy) for more information).",
  "id": "GHSA-f2p5-j6fg-5cxf",
  "modified": "2026-08-20T18:40:13Z",
  "published": "2026-08-20T18:40:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/wagtail/wagtail/security/advisories/GHSA-f2p5-j6fg-5cxf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54260"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/wagtail/PYSEC-2026-613.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/wagtail/wagtail"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Wagtail: Denial of service via unbounded filter specs in the image preview"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.