CVE-2026-54503

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 86% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
19(Track)
EG Risk 19/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity43% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

July 17, 2026

Last Modified

September 15, 2026

Advisory Details (4)

Auto-updated Sep 15, 2026
Patch available. Sources: github, github_commit.
github_commit

commit 781d517a3852 (plone/plone.app.textfield)

Fix landed in plone/plone.app.textfield commit 781d517a3852 — awaiting tagged release

https://github.com/plone/plone.app.textfield/commit/781d517a38524087fe57525a94806684908f852f
github_commit

commit 467638e500d8 (plone/plone.app.textfield)

Fix landed in plone/plone.app.textfield commit 467638e500d8 — awaiting tagged release

https://github.com/plone/plone.app.textfield/commit/467638e500d804c637031387a227a2b02d12a86f
github_commit

commit 0da1aeec2406 (plone/plone.app.textfield)

Fix landed in plone/plone.app.textfield commit 0da1aeec2406 — awaiting tagged release

https://github.com/plone/plone.app.textfield/commit/0da1aeec2406cf640977eb857a03e792d2c7cac2
github Patch Available

Stored XSS by spoofing mime type · Advisory · plone/plone.app.textfield · GitHub

https://github.com/plone/plone.app.textfield/security/advisories/GHSA-4r4f-gg25-rmg5

Vendor Advisories for CVE-2026-54503(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
plone-app-textfield1.0 ... 4.0.0 (37 versions)4.0.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 8× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 11:02 UTCEG score recompute
  3. 2026-09-17 19:31 UTCEPSS rescore
  4. 2026-09-17 10:15 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-15 19:41 UTCEG score recompute
  7. 2026-09-15 19:14 UTCEG score recompute
  8. 2026-09-15 17:34 UTCEG score recompute
  9. 2026-07-30 14:22 UTCEG score recompute
  10. 2026-07-26 11:18 UTCEG score recompute
  11. 2026-07-23 03:19 UTCEG score recompute
  12. 2026-07-17 19:00 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-54503?
CVE-2026-54503 is a medium vulnerability published on July 17, 2026. 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…
When was CVE-2026-54503 disclosed?
CVE-2026-54503 was first published in the National Vulnerability Database on July 17, 2026, with the most recent update on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54503 actively exploited?
CVE-2026-54503 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 85.5% of all scored CVEs.
What is the CVSS score of CVE-2026-54503?
CVE-2026-54503 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-54503?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54503, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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