plone.app.textfield: Stored XSS by spoofing mime type
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.textfieldto 2.0.2. - For Plone 6.1, upgrade
plone.app.textfieldto 3.0.2. - For Plone 6.2, upgrade
plone.app.textfieldto 4.0.1.
Workarounds
There is no known workaround.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | plone-app-textfield | < 2.0.2, >= 3.0.0, < 3.0.2, >= 4.0.0, < 4.0.1 | 2.0.2, 3.0.2, 4.0.1 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-80- Platform
- Python (PyPI)
- Package
plone-app-textfield- Disclosed
- 17.07.2026
- Updated
- 11.10.2026 14:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3497 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-4r4f-gg25-rmg5 - CC BY 4.0
Vulnerability history: plone-app-textfield
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.