CWE-506Weakness · CWE-506

CVE-2026-34424

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Smart Slider 3 Pro version 3.5.1.35 for WordPress and Joomla contains a multi-stage remote access toolkit injected through a compromised update system that allows unauthenticated attackers to execute arbitrary code and commands. Attackers can trigger pre-authentication remote shell execution via HTTP headers, establish authenticated backdoors accepting arbitrary PHP code or OS commands, create hidden administrator accounts, exfiltrate credentials and access keys, and maintain persistence through multiple injection points including must-use plugins and core file modifications.

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

Smart Slider 3 Pro version 3.5.1.35 contains a multi-stage remote access toolkit injected via a compromised update mechanism. The vulnerability allows unauthenticated attackers to achieve pre-authentication remote shell execution through HTTP headers, establish authenticated backdoors accepting arbitrary PHP code or OS commands, create hidden administrator accounts for persistence, and exfiltrate credentials and access keys. Attackers maintain persistence through must-use plugin injections and WordPress core file modifications.

MitigationOrganizations using Smart Slider 3 Pro 3.5.1.35 should immediately remove the plugin, audit for hidden administrator accounts, scan for backdoors in must-use plugins and core files, rotate all credentials, and restore from a known-clean backup or reinstall WordPress core if core modifications are suspected.

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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 Smart Slider 3 Pro installation and version
    Check your WordPress or Joomla installation for the Smart Slider 3 Pro plugin/component. In WordPress, navigate to Plugins > Installed Plugins and look for 'Smart Slider 3' or check the plugin files for version information in the main PHP file header. In Joomla, check Components for Smart Slider 3.
    Affected if Smart Slider 3 Pro version 3.5.1.35 is installed, or any version of Smart Slider 3 Pro is present on a system that received updates between the compromise window and mitigation.
  2. Inspect for hidden administrator accounts
    In WordPress, go to Users > All Users and examine the list for any unrecognized administrator accounts, especially those with unusual usernames, recent creation dates, or suspicious email addresses. Check wp_usermeta table for unexpected user_level or capabilities. In Joomla, navigate to Users > Manage and review all users with Super User privileges.
  3. Search for suspicious backdoor files
    Examine the plugin directory (wp-content/plugins/smart-slider-3/ or equivalent) for newly created or modified PHP files outside the standard structure. Look for files with obfuscated code, base64 encoding, or files with names like shell.php, backdoor.php, or files that accept cmd, exec, or action parameters in URLs.
  4. Check for unexpected must-use plugins
    In WordPress, inspect the wp-content/mu-plugins/ directory for any PHP files that were not intentionally installed by your team. These are auto-loading and can provide persistence. List all files and verify each one was intentionally deployed.
  5. Verify WordPress/Joomla core file integrity
    Compare core WordPress or Joomla files against known clean installations. Check critical files like wp-config.php, index.php in root, and .htaccess for unexpected code insertions, particularly near the top of files or in areas that execute on every request.
  6. Review HTTP header handling indicators
    Examine web server logs and the plugin code for any logic that reads and executes commands from HTTP headers (such as X-Forwarded-For, X-Real-IP, or custom headers). Check the plugin's main entry points for eval(), preg_replace() with /e modifier, or shell_exec() calls triggered by headers.

A system is affected if Smart Slider 3 Pro version 3.5.1.35 is present, or if any version exists alongside unexplained admin accounts, suspicious backdoor files, unauthorized must-use plugins, or modified core files indicating a supply chain compromise.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Organizations using Smart Slider 3 Pro 3.5.1.35 should immediately remove the plugin, audit for hidden administrator accounts, scan for backdoors in must-use plugins and core files, rotate all credentials, and restore from a known-clean backup or reinstall WordPress core if core modifications are suspected.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
Get help mitigating

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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-34424 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2026-34424 in production — separate from our analysis above.

No notes yet

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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