dbcve.org
Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-4335

MEDIUM · 5.4 CVSS v3.1 Published 2026-03-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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
The ShortPixel Image Optimizer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the attachment post_title in all versions up to, and including, 6.4.3. This is due to insufficient output escaping in the getEditorPopup() function and its corresponding media-popup.php template. Specifically, the attachment's post_title is retrieved from the database via get_post() in AjaxController.php (line 435) and passed directly to the view template (line 449), where it is rendered into an HTML input element's value attribute without esc_attr() escaping (media-popup.php line 139). Since WordPress allows Authors to set arbitrary attachment titles (including double-quote characters) via the REST API, a malicious author can craft an attachment title that breaks out of the HTML attribute and injects arbitrary JavaScript event handlers. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts that execute whenever a higher-privileged user (such as an administrator) opens the ShortPixel AI editor popup (Background Removal or Image Upscale) for the poisoned attachment.

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

The ShortPixel Image Optimizer WordPress plugin fails to escape the attachment post_title when rendering it in the AI editor popup. An authenticated Author-level user can set a malicious title containing quote characters via the REST API, breaking out of the HTML input value attribute and injecting arbitrary JavaScript event handlers. When an administrator opens the ShortPixel AI editor popup (Background Removal or Image Upscale) for this poisoned attachment, the injected script executes.

MitigationUpdate ShortPixel Image Optimizer to version 6.4.4 or later which properly escapes the post_title with esc_attr(). If immediate update is not possible, restrict Author-level REST API access or disable the plugin until patched.

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
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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. Confirm ShortPixel Image Optimizer is installed
    In WordPress admin, go to Plugins > Installed Plugins and locate ShortPixel Image Optimizer. Note whether it is active.
    Affected if The plugin is installed and active.
  2. Check the installed plugin version
    Click on the plugin name to view details, or inspect the plugin header in /wp-content/plugins/shortpixel-image-optimiser/shortpixel.php to find the Version field.
    Affected if The version is earlier than 6.4.4 (the fixed version).
  3. Verify AI editor access for lower-privileged users
    Confirm that Author-level users have REST API access to create or modify attachments. Check if users with Author role can access /wp-json/shortpixel/v1/ or similar AI editor endpoints.
    Affected if Authors can access the REST API and create/modify attachments.
  4. Inspect attachment post_titles for injection payloads
    Query the wp_posts table for posts with post_type=attachment and examine post_title values. Look for titles containing quote characters (" or '), onload=, onerror=, javascript:, or other JavaScript event handlers.
    Affected if Any attachment has a post_title containing unescaped quote characters or JavaScript event handler patterns.
  5. Check if administrator has opened the AI editor
    Review access logs or server logs for requests to the ShortPixel AI editor popup (typically triggered when viewing an image in the ShortPixel interface for Background Removal or Image Upscale).
    Affected if An administrator has opened the AI editor for an attachment with a malicious post_title.

The environment is affected if ShortPixel Image Optimizer version is below 6.4.4 and a lower-privileged user can inject a malicious post_title that gets rendered unescaped when an administrator opens the AI editor.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update ShortPixel Image Optimizer to version 6.4.4 or later which properly escapes the post_title with esc_attr(). If immediate update is not possible, restrict Author-level REST API access or disable the plugin until patched.

Recommended fix Moderate confidence

ShortPixel Image Optimizer version 6.4.4 or later

  1. 1. Log in to the WordPress admin dashboard with Administrator privileges
  2. 2. Navigate to Plugins > Installed Plugins
  3. 3. Locate ShortPixel Image Optimizer in the plugin list
  4. 4. Check the current version number to confirm it is 6.4.3 or earlier
  5. 5. If an update is available, click 'Update Now' to upgrade to the latest version (6.4.4 or later)
  6. 6. Alternatively, go to Plugins > Add New > Upload Plugin and upload the latest version from wordpress.org/plugins/shortpixel-image-optimiser/
  7. 7. After updating, verify the plugin version shows 6.4.4 or higher in the Plugins list

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-4335 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-4335 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data