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Smart Slider 3 Pro security vulnerabilities

mySites.guru tracks 2 vulnerabilities in Smart Slider 3 Pro (smartslider3), covering 1 CVE. Every connected Joomla site is checked against them on each audit.

Is my site affected?

Your site is affected if it runs Smart Slider 3 Pro in any of these ranges:

  • version 3.5.1.35 only
  • from 1.999.999 up to and including 3.5.1.33
Latest safe version
We cannot name one release that clears every rule here: one of them records no fixed version. Check the vendor's advisory for the range your site runs.
What to do
Update to the fixed release listed for your version in the table below, or to the newest release from the vendor. Where a range has no fix recorded, check the vendor's release notes before keeping Smart Slider 3 Pro installed.
Check whether your sites are affected

Every Smart Slider 3 Pro vulnerability we track

Newest first. CVSS is the score published in each CVE record, where it has one; the severity column is the rating our check uses.

CVEAffected versionsFixed inSeverityAdded
CVE-2026-34424CVSS 9.3version 3.5.1.35 onlyNot recordedCritical2026-04-08
No CVE idfrom 1.999.999 up to and including 3.5.1.33after 3.5.1.33Medium2026-03-27

What we check for

CriticalCVE-2026-344242026-04-08

CRITICAL: Smart Slider 3 Pro 3.5.1.35 is a COMPROMISED build - treat this site as HACKED

The Smart Slider 3 Pro 3.5.1.35 release for Joomla is a malicious build pushed through a breach of the Nextend update infrastructure. Any Joomla site that installed this version must be treated as fully compromised: the payload creates hidden Super User accounts (typically usernames beginning wpsvc_), drops backdoor files at /cache/cf_check.php and /media/cf_check.php, allows remote code execution and exfiltrates credentials. Update to Smart Slider 3 Pro 3.5.1.36 immediately, manually remove any wpsvc_ Super Users, delete the cf_check.php backdoor files, reinstall Joomla core and every extension from clean sources, and rotate every credential (Joomla admins, FTP, database, hosting and email). Also within this rule: CVE-2026-34424 (NVD record for this same compromised 3.5.1.35 build).

Affected versions: exactly 3.5.1.35

Full advisory: our disclosure post

Medium2026-03-27

Smart Slider 3 <= 3.5.1.33 - Authenticated (Subscriber+) Arbitrary File Read via actionExportAll

The Smart Slider 3 plugin for Joomla is vulnerable to Arbitrary File Read in all versions up to, and including, 3.5.1.33 via the 'actionExportAll' function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information. The Joomla version shares the same vulnerable codebase as the WordPress version.

Affected versions: ≥ 1.999.999 and ≤ 3.5.1.33

Full advisory: our disclosure post

Timeline

  1. 27 March 2026Check added for a flaw with no CVE id (from 1.999.999 up to and including 3.5.1.33)
  2. 8 April 2026Check added for CVE-2026-34424 (version 3.5.1.35 only)
  3. 9 April 2026CVE-2026-34424 record published

References

Each CVE page above links its official cve.org record and its NVD entry.

Smart Slider 3 Pro vulnerability questions

Which versions of Smart Slider 3 Pro are vulnerable?
mySites.guru tracks 2 vulnerabilities in Smart Slider 3 Pro (smartslider3). A site is affected if its installed version is in any of these ranges: version 3.5.1.35 only; from 1.999.999 up to and including 3.5.1.33.
What is the latest safe version of Smart Slider 3 Pro?
We cannot name one release that clears every rule here: one of them records no fixed version. Check the vendor's advisory for the range your site runs.
How do I check which version of Smart Slider 3 Pro my Joomla site runs?
The installed version is listed on the Joomla administrator's Extensions: Manage screen; search it for smartslider3. mySites.guru reads the installed version on every audit of a connected site and checks it against these rules.

Running Smart Slider 3 Pro on a site you manage?

A free audit tells you which of your Joomla and WordPress sites run an affected version, which are out of date, and which have not been backed up. No card required. If a site is already compromised, fix.mysites.guru is a single fixed fee per incident, usually resolved the same day.

This check is part of the mySites.guru Joomla vulnerability scanner, which reads every installed extension's version on each audit. Browse the rest of the Joomla vulnerability database.

CVE identifiers: CVE-2026-34424. Rules current as of 25 October 2026.