Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Owasp | Modsecurity | < 3.0.16 |
Related Weaknesses (CWE)
References
- https://github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2fPatch
- https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16ProductRelease Notes
- https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2ExploitMitigationVendor Advisory
- https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2ExploitMitigationVendor Advisory
FAQ
What is CVE-2026-52747?
CVE-2026-52747 is a vulnerability with a CVSS score of 8.6 (HIGH). 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 r...
How severe is CVE-2026-52747?
CVE-2026-52747 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-52747?
Check the references section above for vendor advisories and patch information. Affected products include: Owasp Modsecurity.