CVE-2025-48866

Description

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Versions prior to 2.9.10 contain a denial of service vulnerability similar to GHSA-859r-vvv8-rm8r/CVE-2025-47947. The `sanitiseArg` (and `sanitizeArg` - this is the same action but an alias) is vulnerable to adding an excessive number of arguments, thereby leading to denial of service. Version 2.9.10 fixes the issue. As a workaround, avoid using rules that contain the `sanitiseArg` (or `sanitizeArg`) action.

How to fix CVE-2025-48866

To remediate CVE-2025-48866, upgrade the affected package to a fixed version below.

—upgrade to 3.0.12 or later
—upgrade to 2.9.10 or later
—upgrade to 2.9.3-3+deb11u4 or later
—upgrade to 2.9.3-3+deb11u4 or later

Is CVE-2025-48866 being exploited?

Low — EPSS is 1.1%, meaning exploitation activity has not been observed at scale.

Affected packages (4)

from 0, < 3.0.12
from 0, < 2.9.10
from 0, < 2.9.3-3+deb11u4
from 0, < 2.9.3-3+deb11u4

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	HIGH7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H