8.6

CVE-2026-52747

ModSecurity: Multipart form-data parser silently strips embedded line breaks from form-field values, enabling request-body inspection bypass

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.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellerowasp-modsecurity
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Produkt ModSecurity
Version < 3.0.16
Status affected
VulnDex Vulnerability Enrichment
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CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 8.6 3.9 4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
CWE-180 Incorrect Behavior Order: Validate Before Canonicalize

The product validates input before it is canonicalized, which prevents the product from detecting data that becomes invalid after the canonicalization step.

https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88
https://github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2f0cc64d896b7815d7
https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16