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.
ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.
DISPUTED Trustwave ModSecurity 3.x through 3.0.4 allows denial of service via a special request. NOTE: The discoverer reports "Trustwave has signaled they are disputing our claims." The CVE suggests that there is a security issue with how ModSecurity handles regular expressions that can result in a Denial of Service condition. The vendor does not consider this as a security issue because1) there is no default configuration issue here. An attacker would need to know that a rule using a potentially problematic regular expression was in place, 2) the attacker would need to know the basic nature of the regular expression itself to exploit any resource issues. It's well known that regular expression usage can be taxing on system resources regardless of the use case. It is up to the administrator to decide on when it is appropriate to trade resources for potential security benefit.
Trustwave ModSecurity 3.0.0 through 3.0.3 allows an attacker to send crafted requests that may, when sent quickly in large volumes, lead to the server becoming slow or unresponsive (Denial of Service) because of a flaw in Transaction::addRequestHeader in transaction.cc.
Trustwave ModSecurity 3.x before 3.0.10 has Inefficient Algorithmic Complexity.
ModSecurity before 2.5.11 treats request parameter values containing single quotes as files, which allows remote attackers to bypass filtering rules and perform other attacks such as cross-site scripting (XSS) attacks via a single quote in a request parameter in the Content-Disposition field of a request with a multipart/form-data Content-Type header.
The modsecurity2 module before 2.7.0 for the Apache HTTP Server allows remote attackers to bypass rules, and deliver arbitrary POST data to a PHP application, via a multipart request in which an invalid part precedes the crafted data.
Description of problem:
Modsecurity 2.7.4 was released today, according to the changelog there a null pointer dereference flaw
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Security Issues:
Fixed Remote Null Pointer DeReference (CVE-2013-2765). When forceRequestBodyVariable action is triggered and a unknown Content-Type is used, modsecurity will crash trying to manipulate msr->mscreqbodychunks->elts however msr->mscreqbodychunks is NULL. (Thanks Younes JAAIDI).
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URL: https://raw.github.com/SpiderLabs/ModSecurity/master/CHANGES
It was reported that the XML files parser of ModSecurity, a security module for the Apache HTTP Server, was vulnerable to XML External Entity attacks. A remote attacker could provide a specially-crafted XML file that, when processed might lead to local files disclosure or, potentially, excessive resources (memory, CPU) consumption.
References: [1] https://bugs.gentoo.org/showbug.cgi?id=464188 [2] https://secunia.com/advisories/52847/ [3] https://github.com/SpiderLabs/ModSecurity/blob/master/CHANGES
Relevant upstream patch: [4] https://github.com/SpiderLabs/ModSecurity/commit/d4d80b38aa85eccb26e3c61b04d16e8ca5de76fe