Unrated

Stored XSS in Plone RichText MIME type handling

IdentifiersCVE-2026-54503CWE-79

CVE-2026-54503 is a stored cross-site scripting vulnerability affecting plone.app.textfield and related Plone deployments using RichText rendering, including environments exposing the issue through plone.restapi. The flaw arises when attacker-controlled RichText content is stored with a spoofed MIME type such that the stored mimeType matches the outputMimeType. In that condition, expected safe_html sanitization is bypassed and unsanitized RichText content can be rendered directly. This allows malicious script content embedded in persisted RichText fields to be stored server-side and later executed in the browsers of users who view the affected content.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation results in stored XSS. An attacker able to submit crafted RichText content can cause arbitrary JavaScript to execute in the browser context of users viewing the malicious content. Depending on the victim’s privileges and browser session, this can enable session theft, unauthorized actions on behalf of the victim, content manipulation, and access to sensitive data exposed to the web application.

Mitigation

If you can’t patch tonight, do this now.

There is no known workaround.

Remediation

Patch, then assume compromise.

Upgrade plone.app.textfield to a fixed release appropriate for the deployed Plone branch: 2.0.2 for Plone 6.0, 3.0.2 for Plone 6.1, or 4.0.1 for Plone 6.2. Deploy the corresponding fixed package versions across affected installations, including environments where RichText content is exposed through plone.restapi.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

PlonePlone.App.Textfieldapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

1 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

1 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1