Description
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGS_POST because src/request_body_processor/multipart.cc overwrites reserved bytes in m_reserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGS_POST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16.
Problem types
CWE-180: Incorrect Behavior Order: Validate Before Canonicalize
Product status
References
github.com/...curity/security/advisories/GHSA-rcw9-2f5r-7p88
github.com/...curity/security/advisories/GHSA-rcw9-2f5r-7p88
github.com/...ommit/875504c2758169c41be1ad2f0cc64d896b7815d7
github.com/...p-modsecurity/ModSecurity/releases/tag/v3.0.16