Products and stacks · Firewalls, appliances and IT tools

PHP2Shell in Nagios XI: is it affected and how to fix it

How to check the PHP version Nagios XI uses

Run the command for your setup. A version at or above 8.2.35, 8.3.36, 8.4.27 or 8.5.12 in its branch is fixed; older branches are fixed only by a vendor build that says so.

php -v
rpm -qa 'php*'

The command-line php can differ from the PHP that serves the site. To be sure, check the web SAPI (a temporary phpinfo() page behind authentication, or the panel's PHP settings) and remove it afterwards. Our version checker compares a version number for you.

🔎 Got a version number? Paste it into the PHP2Shell checker →

How to fix PHP2Shell in Nagios XI

Debian/Ubuntu: sudo apt-get update && sudo apt-get install --only-upgrade 'php8.3*' (repeat for each installed PHP version).
RHEL/Alma/Rocky/Amazon Linux: sudo dnf upgrade 'php*'.
Restart PHP: sudo systemctl restart php8.3-fpm (or php-fpm), and fully restart Apache if it uses mod_php; a graceful reload is not enough.
Distributions often backport the fix without changing the PHP version, so compare the package version or changelog with the vendor's advisory.

Prefer to let an AI agent do the checks? Check if you are affected · Fix with an AI agent

If you cannot patch yet

Set session.upload_progress.enabled = 0 where applications cannot override it (php.ini, php_admin_value in the FPM pool or Apache config), and restart PHP.
On PHP 8.5, set fatal_error_backtraces = 0.
PHP's interim advice also covers memory_limit and a low post_max_size; follow the remediation page exactly, because these settings only reduce some paths.
Restrict access (VPN, IP allowlist) or take the service offline if it runs PHP 8.1 or older with no vendor backport. WAF rules help but are not a fix.

FAQ

Is Nagios XI affected by PHP2Shell?

Affected if the PHP underneath is older than the fixed releases. Nagios XI runs on the operating system's PHP, so the OS PHP update is the fix. We found no product-specific PHP2Shell statement from the vendor as of the check date.

Does updating Nagios XI itself fix CVE-2026-109618 and CVE-2026-109619?

Only if the update contains fixed PHP. PHP2Shell is a flaw in the PHP interpreter, so what matters is the PHP that Nagios XI runs on. Check the version after updating.

Which PHP versions fix PHP2Shell?

PHP 8.2.35, 8.3.36, 8.4.27 and 8.5.12, released 21 October 2026. PHP 8.1 and older get no release from the PHP project; only vendor builds with a backport (or a self-built source patch for 7.4, 8.0 and 8.1) fix them.

What if Nagios XI has no fix yet?

Keep its PHP-based web interface off the internet (VPN or IP allowlist), apply PHP's interim settings such as disabling session upload progress, and install the vendor update as soon as it ships. Interim settings reduce risk but are not a fix.

← All products that bundle PHP

Sources

Outbound links leave this site. We do not host exploit code.

Unofficial summary of public sources. This site is not affiliated with the vendor or the PHP project and hosts no exploit code.