modsecurity — security advisory
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.
- Products
- modsecurity
- Affected versions
- 3.0.10-1, 3.0.11-1, 3.0.12-1, 3.0.12-1.1, 3.0.12-1.1~exp1, 3.0.13-1, 3.0.14-1, 3.0.14-1+deb13u1, 3.0.15-1, 3.0.16-1, 3.0.9-1, 3.0.9-1+deb12u1, 3.0.9-1+deb12u2
- Fixed versions
- 3.0.16-1
- CVEs
- CVE-2026-52747
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 12:16 UTC · Revision 2
Source evidence
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.
osv:DEBIAN-CVE-2026-52747
modsecurity
Fixed versions: Not specified
modsecurity
Fixed versions: Not specified
modsecurity
Fixed versions: 3.0.16-1
Complete source record
{
"id": "25321e00af63b0db86fd71d50e4179084e7c57d547a303d63bb69bd9bdfd188d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-52747",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-52747",
"summary": "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.",
"evidence": "osv:DEBIAN-CVE-2026-52747",
"products": [
{
"name": {
"value": "modsecurity",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.0.10-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.11-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.12-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.12-1.1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.12-1.1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.13-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.14-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.15-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.16-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.9-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.9-1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "3.0.9-1+deb12u2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "modsecurity",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.0.14-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.0.14-1+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "3.0.15-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.0.16-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "modsecurity",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.0.16-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "3.0.14-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.0.15-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-52747",
"aliases": [
"DEBIAN-CVE-2026-52747"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "modsecurity",
"purl": "pkg:deb/debian/modsecurity?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"3.0.10-1",
"3.0.11-1",
"3.0.12-1",
"3.0.12-1.1",
"3.0.12-1.1~exp1",
"3.0.13-1",
"3.0.14-1",
"3.0.15-1",
"3.0.16-1",
"3.0.9-1",
"3.0.9-1+deb12u1",
"3.0.9-1+deb12u2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-52747.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "modsecurity",
"purl": "pkg:deb/debian/modsecurity?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3.0.14-1",
"3.0.14-1+deb13u1",
"3.0.15-1",
"3.0.16-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-52747.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.0.16-1"
}
]
}
],
"package": {
"name": "modsecurity",
"purl": "pkg:deb/debian/modsecurity?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3.0.14-1",
"3.0.15-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-52747.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T11:47:30.525102810Z",
"provider": "osv",
"upstream": [
"CVE-2026-52747"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-52747"
]
},
"related_cves": [
{
"value": "CVE-2026-52747",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 450763,
"published_at": "2026-07-10T22:16:42.697+00:00"
}