{"id":86434,"date":"2026-02-10T22:11:49","date_gmt":"2026-02-10T22:11:49","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T00:00:00","slug":"cve-2025-48866-denial-of-service-vulnerability-in-modsecurity","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-48866-denial-of-service-vulnerability-in-modsecurity\/","title":{"rendered":"CVE-2025-48866: Denial of Service Vulnerability in ModSecurity<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

This report covers an important vulnerability, identified as CVE-2025-48866, that affects ModSecurity, an open-source, cross-platform web application firewall engine for Apache, IIS, and Nginx. The vulnerability can lead to a denial of service, potentially compromising systems or leading to data leaks. It is critical for organizations using ModSecurity to understand and address this vulnerability to protect their systems and data.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-48866
\nSeverity: High (7.5 CVSS v3 Score)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Denial of Service and potential system compromise or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

ModSecurity for Apache | < 2.9.10\nModSecurity for IIS | < 2.9.10\nModSecurity for Nginx | < 2.9.10\n\nHow the Exploit Works<\/strong><\/p>\n

The vulnerability exists within the `sanitiseArg` alias `sanitizeArg` actions of ModSecurity. An attacker can submit a large number of arguments in an HTTP request, which ModSecurity fails to handle properly. This results in a denial of service due to resource exhaustion. The same flaw can potentially be leveraged to compromise the system or leak data.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Here’s a conceptual example of a HTTP request that exploits the vulnerability:<\/p>\n

POST \/vulnerable\/endpoint HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/x-www-form-urlencoded\narg1=value&arg2=value&arg3=value&arg4=value&...&argN=value<\/code><\/pre>\n
In the above example, ‘argN’ represents an excessive number of arguments that exploit the vulnerability.<\/p>\n
Mitigation Guidance<\/strong><\/p>\n
The recommended mitigation is to upgrade to ModSecurity version 2.9.10 or later, which has a fix for this specific vulnerability. If upgrading is not immediately possible, a temporary workaround is to avoid using rules that contain the `sanitiseArg` or `sanitizeArg` action. Utilizing a web application firewall (WAF) or intrusion detection system (IDS) can also provide temporary mitigation.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview This report covers an important vulnerability, identified as CVE-2025-48866, that affects ModSecurity, an open-source, cross-platform web application firewall engine for Apache, IIS, and Nginx. The vulnerability can lead to a denial of service, potentially compromising systems or leading to data leaks. It is critical for organizations using ModSecurity to understand and address this vulnerability […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-86434","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t