ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. In versions 2.9.11 and below, an attacker can override the HTTP response’s Content-Type, which could lead to several issues depending on the HTTP scenario. For example, we have demonstrated the potential for XSS and arbitrary script source code disclosure in the latest version of mod_security2. This issue is fixed in version 2.9.12.

owasp

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. In versions 2.9.8 to before 2.9.11, an empty XML tag can cause a segmentation fault. If SecParseXmlIntoArgs is set to On or OnlyArgs, and the request type is application/xml, and at least one XML tag is empty (eg <foo></foo>), then a segmentation fault occurs. This issue has been patched in version 2.9.11. A workaround involves setting SecParseXmlIntoArgs to Off.

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.

owasp

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.

trustwave

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. Prior to 3.3.3, if a request is made on an URI starting with //, coraza will set a wrong value in REQUEST_FILENAME. For example, if the URI //bar/uploads/foo.php?a=b is passed to coraza: , REQUEST_FILENAME will be set to /uploads/foo.php. This can lead to a rules bypass. This vulnerability is fixed in 3.3.3.

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.

trustwave

A buffer overflow in modsecurity v3.0.12 allows attackers to cause a Denial of Service (DoS) via a crafted input inserted into the name parameter. NOTE: this is disputed by the Supplier because it cannot be reproduced. Also, the product's documentation indicates that it is not guaranteed to be usable with very large values of SecRequestBodyNoFilesLimit (which are required by the claimed issue).

trustwave

ModSecurity / libModSecurity 3.0.0 to 3.0.11 is affected by a WAF bypass for path-based payloads submitted via specially crafted request URLs. ModSecurity v3 decodes percent-encoded characters present in request URLs before it separates the URL path component from the optional query string component. This results in an impedance mismatch versus RFC compliant back-end applications. The vulnerability hides an attack payload in the path component of the URL from WAF rules inspecting it. A back-end may be vulnerable if it uses the path component of request URLs to construct queries. Integrators and users are advised to upgrade to 3.0.12. The ModSecurity v2 release line is not affected by this vulnerability.

owasp

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. Due to the misuse of `log.Fatalf`, the application using coraza crashed after receiving crafted requests from attackers. The application will immediately crash after receiving a malicious request that triggers an error in `mime.ParseMediaType`. This issue was patched in version 3.0.1.

coraza

Trustwave ModSecurity 3.x before 3.0.10 has Inefficient Algorithmic Complexity.

owasp

coreruleset (aka OWASP ModSecurity Core Rule Set) through 3.3.4 does not detect multiple Content-Type request headers on some platforms. This might allow attackers to bypass a WAF with a crafted payload, aka "Content-Type confusion" between the WAF and the backend application. This occurs when the web application relies on only the last Content-Type header. Other platforms may reject the additional Content-Type header or merge conflicting headers, leading to detection as a malformed header.

owasp

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.

owasp

Incorrect handling of '\0' bytes in file uploads in ModSecurity before 2.9.7 may allow for Web Application Firewall bypasses and buffer over-reads on the Web Application Firewall when executing rules that read the FILES_TMP_CONTENT collection.

trustwave · debian

In ModSecurity before 2.9.6 and 3.x before 3.0.8, HTTP multipart requests were 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.

owasp · trustwave · debian

The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body bypass to sequentially exfiltrate small and undetectable sections of data by repeatedly submitting an HTTP Range header field with a small byte range. A restricted resource, access to which would ordinarily be detected, may be exfiltrated from the backend, despite being protected by a web application firewall that uses CRS. Short subsections of a restricted resource may bypass pattern matching techniques and allow undetected access. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively and to configure a CRS paranoia level of 3 or higher.

owasp · fedoraproject · debian

The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body bypass. A client can issue an HTTP Accept header field containing an optional "charset" parameter in order to receive the response in an encoded form. Depending on the "charset", this response can not be decoded by the web application firewall. A restricted resource, access to which would ordinarily be detected, may therefore bypass detection. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.

owasp · fedoraproject · debian

The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or the deprecated Content-Transfer-Encoding multipart MIME header fields that will not be decoded and inspected by the web application firewall engine and the rule set. The multipart payload will therefore bypass detection. A vulnerable backend that supports these encoding schemes can potentially be exploited. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised upgrade to 3.2.2 and 3.3.3 respectively. The mitigation against these vulnerabilities depends on the installation of the latest ModSecurity version (v2.9.6 / v3.0.8).

owasp · fedoraproject · debian

The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.

owasp · fedoraproject · debian

Modsecurity owasp-modsecurity-crs 3.2.0 (Paranoia level at PL1) has a SQL injection bypass vulnerability. Attackers can use the comment characters and variable assignments in the SQL syntax to bypass Modsecurity WAF protection and implement SQL injection attacks on Web applications.

owasp · debian

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.

owasp · trustwave · f5 · debian · oracle

OWASP ModSecurity Core Rule Set 3.1.x before 3.1.2, 3.2.x before 3.2.1, and 3.3.x before 3.3.2 is affected by a Request Body Bypass via a trailing pathname.

owasp · fedoraproject · debian

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.

owasp