Guide How to Fix PHP2Shell (CVE-2026-109618/109619) on Plesk

Guide How to Fix PHP2Shell (CVE-2026-109618/109619) on Plesk - Printable Version

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How to Fix PHP2Shell (CVE-2026-109618/109619) on Plesk - JAY - 10-22-2026

How to Fix PHP2Shell (CVE-2026-109618/109619) on Plesk

On 21 October 2026 PHP released emergency fixes for two critical bugs, CVE-2026-109618 and CVE-2026-109619 ("PHP2Shell"). They can let an attacker run code on your server without logging in, and attacks are already happening. This guide shows how to patch a server running Plesk, step by step.

New to PHP2Shell? Read the overview first: PHP2Shell explained: what it is and how to fix it.

The fixed versions
Your PHP must be at least: 8.5.12, 8.4.27, 8.3.36 or 8.2.35. Older branches (7.4 to 8.1) need a patched build from your vendor. Update every PHP version installed, not just the one your main site uses.

Step 1: See which PHP versions you have
In Plesk, go to Tools & Settings > PHP Settings to see every PHP handler and its version. From the terminal:

Code:

plesk bin php_handler --list

Plesk builds its own PHP packages with the upstream version number, so a handler showing 8.3.36 means the fix is in.

Step 2: Update the PHP components
In the panel: Tools & Settings > Updates (Plesk Installer) and install the available component updates. Or from the terminal, as root:

Code:

plesk installer --select-release-current --upgrade-installed-components

If no PHP updates show up yet, Plesk may not have published them; check again later and apply the temporary protection below.

Step 3: Restart PHP-FPM

Code:

systemctl list-units --type=service | grep -i 'plesk-php.*fpm'
systemctl restart plesk-php83-fpm   # repeat for each one listed
plesk bin php_handler --reread

Step 4: Confirm
Run

Code:

plesk bin php_handler --list

again and check every handler shows a fixed version.

Check the version your websites really use
The command line can show a different PHP from the one serving websites. To be sure, create a file called

Code:

v.php

in a website's folder containing:

Code:

<?php echo PHP_VERSION;

Open

Code:

https://your-domain/v.php

, check the number, then delete the file.

Can't update yet? Temporary protection
These settings reduce the risk until a patched version is installed. They are not a full fix. Add them to the php.ini of each PHP version (Tools & Settings > PHP Settings, click a PHP version, then php.ini), then restart PHP:

Code:

session.upload_progress.enabled = 0
; PHP 8.5 only:
fatal_error_backtraces = 0

Don't set these with

Code:

ini_set()

or a

Code:

.user.ini

file; they must be set server-side. The PHP team also suggests

Code:

memory_limit = -1

against CVE-2026-109618, but that removes PHP's memory cap, so only use it short-term and with care.

After patching: check you weren't hit
Attacks started on 17 October, before the fix existed. Spend ten minutes on these checks:

PHP files created or changed since 17 October that you don't recognise, especially in upload folders:

Code:
find /var/www/vhosts -name "*.php" -newermt 2026-10-17 -type f 2>/dev/null | head -50
Unknown cron jobs:
Code:
crontab -l
for root and each site user.
Unusual CPU use (crypto miners are common):
Code:
ps aux --sort=-%cpu | head

If something looks wrong, change the passwords and API keys your PHP apps use, because these bugs can leak memory contents.

Questions? Ask in Plesk Security Support with your OS, Plesk version and the output of your PHP version check.

Sources (checked 22 October 2026): Tenable PHP2Shell FAQ · Qualys: mitigate and patch PHP2Shell