GHSA-4R4F-GG25-RMG5

Vulnerability from github – Published: 2026-07-17 18:35 – Updated: 2026-07-17 18:35
VLAI
Summary
plone.app.textfield: Stored XSS by spoofing mime type
Details

Impact

A stored XSS affecting RichText fields. RichTextValue.output returns the raw, unsanitized stored value whenever the stored mimeType equals the outputMimeType. Because the safe-HTML output type (text/x-html-safe) is the type that signifies "already sanitized", any value whose stored mimeType equals it bypasses the safe_html transform entirely on render. The transform itself is sound — it correctly strips on* event-handler attributes and javascript:/data: URIs; the defect is that it is never invoked for these values. The unsanitized value is then emitted via tal:content="structure ...", which performs no escaping, so the payload executes in the viewer's browser.

This can be a problem when a RichText field is wrongly defined in code with a mimeType and outputMimeType that are the same, or when the REST API is used to the same effect.

Patches

The problem has been patched:

  • For Plone 6.0, upgrade plone.app.textfield to 2.0.2.
  • For Plone 6.1, upgrade plone.app.textfield to 3.0.2.
  • For Plone 6.2, upgrade plone.app.textfield to 4.0.1.

Workarounds

There is no known workaround.

Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "plone.app.textfield"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "plone.app.textfield"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "plone.app.textfield"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54503"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-80"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-17T18:35:57Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nA stored XSS affecting RichText fields. RichTextValue.output returns the raw, unsanitized stored value whenever the stored mimeType equals the outputMimeType. Because the safe-HTML output type (`text/x-html-safe`) is the type that signifies \"already sanitized\", any value whose stored mimeType equals it bypasses the safe_html transform entirely on render. The transform itself is sound \u2014 it correctly strips `on*` event-handler attributes and `javascript:/data:` URIs; the defect is that it is never invoked for these values. The unsanitized value is then emitted via `tal:content=\"structure ...\"`, which performs no escaping, so the payload executes in the viewer\u0027s browser. \n\nThis can be a problem when a RichText field is wrongly defined in code with a `mimeType` and `outputMimeType` that are the same, or when the REST API is used to the same effect.\n\n### Patches\nThe problem has been patched:\n\n* For Plone 6.0, upgrade `plone.app.textfield` to 2.0.2.\n* For Plone 6.1, upgrade `plone.app.textfield` to 3.0.2.\n* For Plone 6.2, upgrade `plone.app.textfield` to 4.0.1.\n\n### Workarounds\nThere is no known workaround.",
  "id": "GHSA-4r4f-gg25-rmg5",
  "modified": "2026-07-17T18:35:57Z",
  "published": "2026-07-17T18:35:57Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/plone/plone.app.textfield/security/advisories/GHSA-4r4f-gg25-rmg5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/plone/plone.app.textfield"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "plone.app.textfield: Stored XSS by spoofing mime type "
}



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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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Nomenclature

  • 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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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