What PlanetHoster said on October 21
PlanetHoster published a dedicated notice page about the vulnerability, available in French and English. At 4 PM, Paris time, the fixes released by the PHP project were being deployed « across all our servers. » At 6:50 PM, deployment was still ongoing. At 10:10 PM, they indicated they were monitoring a possible additional vulnerability affecting version 8.5.12 as well and maintained their protections. In the meantime, two emergency measures were taken: the session.upload_progress functionality was disabled, and multipart/form-data requests were blocked, which may return a 403 error to your forms with attachments and file uploads as long as the measure remains active. The page concludes: « no action is required on your part, » and support responds to questions by citing « PHP2Shell. »
Two caveats, the same as with other hosts. Emergency measures do not replace the corrected version, and a site remaining on a branch no longer maintained by the PHP project, such as 8.1 or older, will not receive a fix unless PlanetHoster announces a custom fix, which the page does not mention.
Where to change the PHP version depending on your control panel
On N0C, the current panel: in the menu, open Languages, then PHP. The list PHP Versions displays the current version; select another one and click on Apply. PHP Extensions and Options are used to enable extensions and configure php.ini, and the Reset button restores default values. The setting applies to the entire N0C web project: two sites requiring different versions must be in separate projects.
On an old cPanel account, the pre-N0C era: tool Select PHP Version, select the version, then Set as current; extensions are managed via Switch to PHP extensions, and the setting applies to the entire cPanel account.
On HybridCloud, with WHM: MultiPHP Manager, section Set PHP Version per Domain, select the domain, choose the version, ApplyThe update takes about one minute.
Which version to choose
PHP 8.3 or 8.4: the safest choice for WordPress, WooCommerce, or a recent tool. The corrected versions are 8.3.36 and 8.4.27, with security fixes until 2027 and 2028. N0C offers both, as well as 8.5.
PHP 8.2: corrected in 8.2.35, but the branch ends on December 31, 2026.
PHP 8.1 and older: N0C allows choosing all versions from 4.4 to 8.1 without warning. No official corrected version exists for these branches. If your site is on one of these, upgrading the version is not an option—it’s the security update itself. Check beforehand that your theme and plugins support the target version: WordPress works from 7.4 to 8.5; it’s the old plugins that break.
Check that the patch is properly installed
The dashboard displays the branch, not the exact patch number. The full number appears on a phpinfo page or, on WordPress, in Tools, then Site Health, tab Info, section Server. The numbers to look for are 8.2.35, 8.3.36, 8.4.27, or 8.5.12. If you see a lower number, the deployment hasn’t reached your server yet: the PlanetHoster notice page shows the progress, and the verification tool reads the number once the server displays it.
If the site breaks after the update
The first reflex: go back to the previous version through the same menu, long enough to update the faulty extension or theme, then revert. Before any action, back up off the server and test on a copy. A blank page or a 500 error right after the change almost always comes from a missing PHP extension in the Extensions tab or a function removed between branches. And if your forms return a 403 error tonight, it’s not your version change: it’s the temporary blocking of multipart uploads decided by your host.
And if you don’t want to handle it yourself
I’ll do this remotely for you: backup, test on a copy, version update, extension check, patch verification, test of the homepage, admin panel, and a payment, then a written report. Write to me with your site’s link, I’ll reply within 24 hours. The same guides exist for OVHcloud, o2switch, IONOS, Hostinger and Infomaniak.
Sources: N0C knowledge base « PHP », PlanetHoster cPanel guide « Modify PHP Values », PlanetHoster HybridCloud guide « Managing PHP », PlanetHoster review dated October 21, 2026, fixed versions available on php.net.
