CVE-2026-54503 json
plone.app.textfield: Stored XSS by spoofing mime type
published 2026-07-17 3 mo ago modified 2026-09-30 39 d ago also GHSA-4r4f-gg25-rmg5 , PYSEC-2026-3497 , EUVD-2026-78836
- cvss
- 4.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 34%
- public exploits
- 0
- none known
Summary
plone.app.textfield provides a zope.schema-style field type called RichText for storing a value with a related MIME type. Prior to 2.0.2, 3.0.2, and 4.0.1, depending on the release line, RichTextValue.output returns an unsanitized stored RichText value when mimeType equals outputMimeType, including values that claim the text/x-html-safe output type. This equality shortcut bypasses the safe_html transform even though the transform itself correctly removes event-handler attributes and unsafe URI schemes. Equal types can result from a RichText field configured with the same mimeType and outputMimeType or from REST API input that supplies text/x-html-safe as its content type. The raw stored value is then emitted through tal:content=structure without escaping, allowing a user who can set a RichText field to store JavaScript that executes in a viewer's browser. This issue is fixed in versions 2.0.2, 3.0.2, and 4.0.1.
Patch / fix
- pypi plone-app-textfield 2.0.2, 3.0.2, 4.0.1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 54 d ago
Exploit prediction
0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
| GitHub | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
| OSV | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| 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 |
Affected products
- plone plone.app.textfield
Classification
- Weakness
-
- CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page
References
- github.com /plone/plone.app.textfield/commit/0da1aeec2406cf640977eb857a03e792d2c7cac2
- github.com /plone/plone.app.textfield/commit/467638e500d804c637031387a227a2b02d12a86f
- github.com /plone/plone.app.textfield/commit/781d517a38524087fe57525a94806684908f852f
-
github.com
/plone/plone.app.textfield/security/advisories/GHSA-4r4f-gg25-rmg5
web
-
github.com
/plone/plone.app.textfield
package
-
pypi.org
/project/plone-app-textfield
package
-
github.com
/advisories/GHSA-4r4f-gg25-rmg5
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-54503
advisory
Sources
- CVE List CVE-2026-54503
- GitHub Advisory GHSA-4r4f-gg25-rmg5
- NVD CVE-2026-54503
- OSV PYSEC-2026-3497
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.