Low
Security advisory
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw affects libslirp versions prior to 4.6.0.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-3593
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 07:58 UTC · Revision 1
Source evidence
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw affects libslirp versions prior to 4.6.0.
osv:CVE-2021-3593
Complete source record
{
"id": "2543239bdfe956bf067f4715ccee670d7678d33681c45afd6c11b8900edbea11",
"url": "https://osv.dev/vulnerability/CVE-2021-3593",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-3593",
"summary": "An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw affects libslirp versions prior to 4.6.0.",
"evidence": "osv:CVE-2021-3593",
"products": [],
"severity": "low",
"structured": {
"id": "CVE-2021-3593",
"aliases": [
"CVE-2021-3593"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://gitlab.freedesktop.org/slirp/libslirp",
"type": "GIT",
"events": [
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},
{
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3593.json"
}
}
],
"modified": "2026-10-24T10:31:00.999699130Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2023/03/msg00013.html",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GCKWZWY64EHTOQMLVLTSZ4AA27EWRJMH/",
"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SGPQZFVJCFGDSISFXPCQTTBBD7QZLJKI/",
"https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html",
"https://security.gentoo.org/glsa/202107-44",
"https://security.netapp.com/advisory/ntap-20210805-0004/",
"https://bugzilla.redhat.com/show_bug.cgi?id=1970487"
],
"provider_metadata": {
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],
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}
],
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{
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],
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]
},
{
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},
{
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],
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}
],
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}
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]
}
},
"related_cves": [
{
"value": "CVE-2021-3593",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 439694,
"published_at": "2021-06-15T21:15:09.677+00:00"
}