Critical
Security advisory
URI_FUNC() in UriParse.c in uriparser before 0.9.1 has an out-of-bounds read (in uriParse*Ex* functions) for an incomplete URI with an IPv6 address containing an embedded IPv4 address, such as a "//[::44.1" address.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2018-20721
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:25 UTC · Revision 1
Source evidence
URI_FUNC() in UriParse.c in uriparser before 0.9.1 has an out-of-bounds read (in uriParse*Ex* functions) for an incomplete URI with an IPv6 address containing an embedded IPv4 address, such as a "//[::44.1" address.
osv:CVE-2018-20721
Complete source record
{
"id": "d74eda7878cdb0f752377e52321cbcc46a146b7fa06599ea2beae939534c5980",
"url": "https://osv.dev/vulnerability/CVE-2018-20721",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2018-20721",
"summary": "URI_FUNC() in UriParse.c in uriparser before 0.9.1 has an out-of-bounds read (in uriParse*Ex* functions) for an incomplete URI with an IPv6 address containing an embedded IPv4 address, such as a \"//[::44.1\" address.",
"evidence": "osv:CVE-2018-20721",
"products": [],
"severity": "critical",
"structured": {
"id": "CVE-2018-20721",
"aliases": [
"CVE-2018-20721"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/uriparser/uriparser",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "f8ccdfd76b2d46b7162c17e01baee4de402947b5"
},
{
"fixed": "cef25028de5ff872c2e1f0a6c562eb3ea9ecbce4"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:uriparser_project:uriparser:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "0.9.1"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "cef25028de5ff872c2e1f0a6c562eb3ea9ecbce4"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"uriparser-0.9.0",
"uriparser-0.8.6",
"uriparser-0.8.5",
"uriparser-0.8.4",
"uriparser-0.8.3",
"uriparser-0.8.2",
"uriparser-0.8.1",
"uriparser-0.8.0.1",
"uriparser-0.8.0",
"uriparser-0.7.5",
"uriparser-0.7.9",
"uriparser-0.7.8",
"uriparser-0.7.7",
"uriparser-0.7.6",
"uriparser-0.7.4",
"uriparser-0.7.3",
"uriparser-0.7.2",
"uriparser-0.7.1",
"uriparser-0.7.0",
"uriparser-0.6.4",
"uriparser-0.6.3",
"uriparser-0.6.2",
"uriparser-0.6.1",
"uriparser-0.6.0",
"uriparser-0.5.2",
"uriparser-0.5.1",
"uriparser-0.5.0",
"uriparser-0.4.0",
"uriparser-0.3.4",
"uriparser-0.3.3",
"uriparser-0.3.2",
"uriparser-0.3.1",
"uriparser-0.3.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-20721.json",
"vanir_signatures": [
{
"id": "CVE-2018-20721-4434bc5e",
"digest": {
"threshold": 0.9,
"line_hashes": [
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"215581821721008525431947121099457754519",
"201805718942423830449133541022097869316",
"260694568477623545972598510528977911363"
]
},
"source": "https://github.com/uriparser/uriparser/commit/cef25028de5ff872c2e1f0a6c562eb3ea9ecbce4",
"target": {
"file": "src/UriParse.c"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
},
{
"id": "CVE-2018-20721-b03f06b3",
"digest": {
"threshold": 0.9,
"line_hashes": [
"338453238041534226044660422606642359923",
"158901063685954033803528095984396445438",
"43762078588843109887431033654435444035"
]
},
"source": "https://github.com/uriparser/uriparser/commit/cef25028de5ff872c2e1f0a6c562eb3ea9ecbce4",
"target": {
"file": "test/test.cpp"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
}
],
"vanir_signatures_modified": "2026-10-20T13:28:58Z"
}
}
],
"modified": "2026-10-20T13:28:58.307738421Z",
"provider": "osv",
"references": [
"https://github.com/uriparser/uriparser/blob/master/ChangeLog",
"https://lists.debian.org/debian-lts-announce/2019/02/msg00028.html",
"https://lists.debian.org/debian-lts-announce/2021/11/msg00029.html",
"https://github.com/uriparser/uriparser/commit/cef25028de5ff872c2e1f0a6c562eb3ea9ecbce4"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*",
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
},
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2018-20721",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 387728,
"published_at": "2019-01-16T14:29:00.247+00:00"
}