CVE-2026-54503: Plone.app.textfield Cross-Site Scripting Vulnerability
MODERATECVE-2026-54503 is a MODERATE (CVSS 4.3) cross-site scripting vulnerability (CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)) affecting Plone.app.textfield libraries in the PyPI ecosystem. The issue involves stored xss by spoofing mime type. Remediation is available by upgrading affected packages to version 2.0.2, 3.0.2, 4.0.1.
CVE-2026-54503 at a Glance
Security Impact
CVSS: 4.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N).
How to Fix CVE-2026-54503
To remediate this vulnerability, upgrade all affected Plone.app.textfield dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
pip install plone.app.textfield>=2.0.2pip install plone.app.textfield>=3.0.2pip install plone.app.textfield>=4.0.1Run the following command in your project directory to verify that all resolved dependencies use the patched release:
pip show plone.app.textfieldHow to Check if You Are Affected
To determine whether your Python environment is affected by CVE-2026-54503, inspect your installed packages using pip:
pip show plone.app.textfieldAnalyze the terminal output to locate any version of Plone.app.textfield in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.2), your application is affected.
Note: The pip show plone.app.textfield command checks currently installed packages in your active Python environment.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS), where the product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. In Plone.app.textfield, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-54503 Affected Plone.app.textfield Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
plone.app.textfield
|
PyPI |
< 2.0.2
|
2.0.2
|
|
plone.app.textfield
|
PyPI |
≥ 3.0.0
< 3.0.2
|
3.0.2
|
|
plone.app.textfield
|
PyPI |
≥ 4.0.0
< 4.0.1
All 1 versions
4.0.0
|
4.0.1
|
References
Frequently Asked Questions
What is CVE-2026-54503?
Which Plone.app.textfield versions are affected?
What version fixes CVE-2026-54503?
Is plone.app.textfield affected?
What is the CVSS score of CVE-2026-54503?
What CWE is associated with CVE-2026-54503?
How can I check PyPI dependencies for CVE-2026-54503?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-4r4f-gg25-rmg5",
"modified" : "2026-07-17T18:35:57Z",
"published" : "2026-07-17T18:35:57Z",
"aliases" : [ "CVE-2026-54503" ],
"summary" : "plone.app.textfield: Stored XSS by spoofing mime type ",
"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 — 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. \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.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "PyPI",
"name" : "plone.app.textfield"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "2.0.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "PyPI",
"name" : "plone.app.textfield"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.0.0"
}, {
"fixed" : "3.0.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "PyPI",
"name" : "plone.app.textfield"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.0.0"
}, {
"fixed" : "4.0.1"
} ]
} ],
"versions" : [ "4.0.0" ]
} ],
"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"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-80" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-07-17T18:35:57Z",
"nvd_published_at" : null
}
}