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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-55596

HIGH · 8.7 CVSS v3.1 Published 2026-07-08
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
91/100
Remediation priority · Urgent
Remotely reachable Patch available 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Plate is a rich-text editor with AI and shadcn/ui. From 53.0.0 until 53.1.4, the media embed renderer trusts serialized provider or sourceUrl metadata in useMediaState and skips parseMediaUrl protocol validation, allowing a crafted Plate document to set a known video provider while keeping url as a javascript: iframe source that the registry MediaEmbedElement renders directly as an iframe src when a victim opens the document. This issue is fixed in version 53.1.4.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A stored XSS vulnerability in Plate rich-text editor's media embed renderer (versions 53.0.0-53.1.4) allows attackers to embed malicious javascript: URLs via crafted documents. The useMediaState component trusts serialized provider/sourceUrl metadata without validating protocols, enabling the MediaEmbedElement to render arbitrary JavaScript in iframes when victims open specially crafted documents.

MitigationUpgrade to Plate version 53.1.4 which implements parseMediaUrl protocol validation to reject javascript: and other dangerous protocols in media embeds.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Plate installation and version
    Check your package.json or node_modules for @udecode/plate or plate package version. Run: npm list @udecode/plate or grep -r '"@udecode/plate"' package.json
    Affected if Installed version is below 53.1.4 and the media embed component is in use
  2. Verify media embed feature is enabled
    Search your codebase for MediaEmbedElement, PlateMediaEmbed, or media-embed plugin configuration. Check if createMediaEmbedPlugin is used in your plugin registration
    Affected if Media embed plugin is registered and active in your Plate editor configuration
  3. Inspect stored documents for embedded media
    If you have a database, query for documents containing media embed data. Look for serialized provider/sourceUrl in your document store. Search for entries with mediaEmbed type in your content
    Affected if Documents contain media embed nodes with sourceUrl values that use non-standard protocols (javascript:, data:, etc.)
  4. Check parseMediaUrl validation exists
    Search your node_modules/@udecode/plate-media-embed for the parseMediaUrl function. Verify it contains protocol validation logic (should check for http/https and reject javascript:, data:, etc.)
    Affected if The parseMediaUrl function is missing or does not validate protocols before using the URL in iframe src

You are affected if Plate version is below 53.1.4 AND the media embed feature is enabled, especially if untrusted documents with embedded media are processed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Interim mitigation

Upgrade to Plate version 53.1.4 which implements parseMediaUrl protocol validation to reject javascript: and other dangerous protocols in media embeds.

Recommended fix High confidence

53.1.4

  1. Update the @udecode/plate-media package (or the main plate package) to version 53.1.4 or later using your package manager (e.g., npm install @udecode/[email protected], yarn add @udecode/[email protected], or pnpm add @udecode/[email protected])
  2. After upgrading, verify that media embeds in Plate documents render correctly and that the javascript: protocol is properly blocked in iframe sources

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-55596 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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