Libmodsecurity is one component of the ModSecurity v3 project. The library codebase serves as an interface to ModSecurity Connectors taking in web traffic and applying traditional ModSecurity processing. A bug that exists only in Libmodsecurity3 version 3.0.13 means that, in 3.0.13, Libmodsecurity3 can't decode encoded HTML entities if they contains leading zeroes. Version 3.0.14 contains a fix. No known workarounds are available.
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Versions up to and including 2.9.8 are vulnerable to denial of service in one special case (in stable released versions): when the payload's content type is application/json, and there is at least one rule which does a sanitiseMatchedBytes action. A patch is available at pull request 3389 and expected to be part of version 2.9.9. No known workarounds are available.
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.
Trustwave ModSecurity 3.x before 3.0.10 has Inefficient Algorithmic Complexity.
Trustwave ModSecurity 3.0.5 through 3.0.8 before 3.0.9 allows a denial of service (worker crash and unresponsiveness) because some inputs cause a segfault in the Transaction class for some configurations.
A vulnerability was found in ModSecurity. This issue occurs when HTTP multipart requests are incorrectly parsed and could bypass the Web Application Firewall. NOTE: This is related to CVE-2022-39956, but can be considered independent changes to the ModSecurity (C language) codebase.
In ModSecurity before 2.9.7, FILESTMPCONTENT sometimes lacked the complete content. This can lead to a Web Application Firewall bypass.
https://github.com/SpiderLabs/ModSecurity/pull/2857/commits/4324f0ac59f8225aa44bc5034df60dbeccd1d334 https://github.com/SpiderLabs/ModSecurity/releases/tag/v2.9.7 https://github.com/SpiderLabs/ModSecurity/pull/2857
DISPUTED ModSecurity 3.0.0 has XSS via an onerror attribute of an IMG element. NOTE: a third party has disputed this issue because it may only apply to environments without a Core Rule Set configured.
ModSecurity 3.x before 3.0.4 mishandles key-value pair parsing, as demonstrated by a "string index out of range" error and worker-process crash for a "Cookie: =abc" header.
apache2/modsecurity.c in ModSecurity before 2.7.6 allows remote attackers to bypass rules by using chunked transfer coding with a capitalized Chunked value in the Transfer-Encoding HTTP header.
The multipart processor in ModSecurity before 2.5.9 allows remote attackers to cause a denial of service (crash) via a multipart form datapost request with a missing part header name, which triggers a NULL pointer dereference.
ModSecurity before 2.6.6, when used with PHP, does not properly handle single quotes not at the beginning of a request parameter value in the Content-Disposition field of a request with a multipart/form-data Content-Type header, which allows remote attackers to bypass filtering rules and perform other attacks such as cross-site scripting (XSS) attacks. NOTE: this vulnerability exists because of an incomplete fix for CVE-2009-5031.
The PDF XSS protection feature in ModSecurity before 2.5.8 allows remote attackers to cause a denial of service (Apache httpd crash) via a request for a PDF file that does not use the GET method.