HighFix available
civetweb — security advisory
A vulnerability in the CivetWeb library's function mg_handle_form_request allows remote attackers to trigger a denial of service (DoS) condition. By sending a specially crafted HTTP POST request containing a null byte in the payload, the server enters an infinite loop during form data parsing. Multiple malicious requests will result in complete CPU exhaustion and render the service unresponsive to further requests. This issue was fixed in commit 782e189. This issue affects only the library, standalone executable pre-built by vendor is not affected.
- Products
- civetweb
- Affected versions
- 1.13+dfsg-5, 1.15+dfsg-1, 1.15+dfsg-3, 1.16+dfsg-1, 1.16+dfsg-1build1, 1.16+dfsg-2, 1.16+dfsg-3, 1.16+dfsg-4
- Fixed versions
- 1.15+dfsg-3ubuntu0.1~esm1, 1.16+dfsg-1ubuntu0.1, 1.16+dfsg-3ubuntu0.1
- CVEs
- CVE-2025-9648
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:52 UTC · Revision 1
Source evidence
A vulnerability in the CivetWeb library's function mg_handle_form_request allows remote attackers to trigger a denial of service (DoS) condition. By sending a specially crafted HTTP POST request containing a null byte in the payload, the server enters an infinite loop during form data parsing. Multiple malicious requests will result in complete CPU exhaustion and render the service unresponsive to further requests. This issue was fixed in commit 782e189. This issue affects only the library, standalone executable pre-built by vendor is not affected.
osv:UBUNTU-CVE-2025-9648
civetweb
Fixed versions: 1.15+dfsg-3ubuntu0.1~esm1
civetweb
Fixed versions: 1.16+dfsg-1ubuntu0.1
civetweb
Fixed versions: Not specified
civetweb
Fixed versions: Not specified
civetweb
Fixed versions: 1.16+dfsg-3ubuntu0.1
Complete source record
{
"id": "bc43524503fdd18fe6084cb95fb3484a358ffe51c08870b2d7bb2697e36929e4",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2025-9648",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2025-9648",
"summary": "A vulnerability in the CivetWeb library's function mg_handle_form_request allows remote attackers to trigger a denial of service (DoS) condition. By sending a specially crafted HTTP POST request containing a null byte in the payload, the server enters an infinite loop during form data parsing. Multiple malicious requests will result in complete CPU exhaustion and render the service unresponsive to further requests. This issue was fixed in commit 782e189. This issue affects only the library, standalone executable pre-built by vendor is not affected.",
"evidence": "osv:UBUNTU-CVE-2025-9648",
"products": [
{
"name": {
"value": "civetweb",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.15+dfsg-3ubuntu0.1~esm1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "1.13+dfsg-5",
"evidence": "/affected/0/versions"
},
{
"value": "1.15+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.15+dfsg-3",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "civetweb",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.16+dfsg-1ubuntu0.1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "1.16+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.16+dfsg-1build1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "civetweb",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.16+dfsg-2",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "civetweb",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.16+dfsg-3",
"evidence": "/affected/3/versions"
},
{
"value": "1.16+dfsg-4",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "civetweb",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.16+dfsg-3ubuntu0.1",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": [
{
"value": "1.16+dfsg-2",
"evidence": "/affected/4/versions"
},
{
"value": "1.16+dfsg-3",
"evidence": "/affected/4/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2025-9648",
"aliases": [
"UBUNTU-CVE-2025-9648"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.15+dfsg-3ubuntu0.1~esm1"
}
]
}
],
"package": {
"name": "civetweb",
"purl": "pkg:deb/ubuntu/civetweb?arch=source&distro=esm-apps%2Fjammy",
"ecosystem": "Ubuntu:Pro:22.04:LTS"
},
"versions": [
"1.13+dfsg-5",
"1.15+dfsg-1",
"1.15+dfsg-3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-9648.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "civetweb",
"binary_version": "1.15+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "libcivetweb1",
"binary_version": "1.15+dfsg-3ubuntu0.1~esm1"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.16+dfsg-1ubuntu0.1"
}
]
}
],
"package": {
"name": "civetweb",
"purl": "pkg:deb/ubuntu/civetweb?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"1.16+dfsg-1",
"1.16+dfsg-1build1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-9648.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "civetweb",
"binary_version": "1.16+dfsg-1ubuntu0.1"
},
{
"binary_name": "libcivetweb1",
"binary_version": "1.16+dfsg-1ubuntu0.1"
}
],
"availability": "No subscription required"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "civetweb",
"purl": "pkg:deb/ubuntu/civetweb?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"1.16+dfsg-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-9648.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "civetweb",
"binary_version": "1.16+dfsg-2"
},
{
"binary_name": "libcivetweb1",
"binary_version": "1.16+dfsg-2"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "civetweb",
"purl": "pkg:deb/ubuntu/civetweb?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"1.16+dfsg-3",
"1.16+dfsg-4"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-9648.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "civetweb",
"binary_version": "1.16+dfsg-4"
},
{
"binary_name": "libcivetweb1",
"binary_version": "1.16+dfsg-4"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.16+dfsg-3ubuntu0.1"
}
]
}
],
"package": {
"name": "civetweb",
"purl": "pkg:deb/ubuntu/civetweb?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1.16+dfsg-2",
"1.16+dfsg-3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-9648.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "civetweb",
"binary_version": "1.16+dfsg-3ubuntu0.1"
},
{
"binary_name": "libcivetweb1",
"binary_version": "1.16+dfsg-3ubuntu0.1"
}
],
"availability": "No subscription required"
}
}
],
"modified": "2026-10-17T12:59:39.740329857Z",
"provider": "osv",
"upstream": [
"CVE-2025-9648"
],
"references": [
"https://ubuntu.com/security/CVE-2025-9648",
"https://www.cve.org/CVERecord?id=CVE-2025-9648",
"https://github.com/civetweb/civetweb/issues/1348",
"https://github.com/civetweb/civetweb/commit/782e18903515f43bafbf2e668994e82bdfa51133",
"https://cert.pl/en/posts/2025/09/CVE-2025-9648",
"https://github.com/civetweb/civetweb",
"https://ubuntu.com/security/notices/USN-8749-1"
]
},
"related_cves": [
{
"value": "CVE-2025-9648",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 359700,
"published_at": "2025-09-29T12:15:00+00:00"
}