LowFix available
libslirp, qemu — security advisory
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp_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
- libslirp, qemu
- Affected versions
- Not specified
- Fixed versions
- 1:4.1-2, 4.6.1-1
- CVEs
- CVE-2021-3594
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 00:36 UTC · Revision 1
Source evidence
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp_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:DEBIAN-CVE-2021-3594
libslirp
Fixed versions: 4.6.1-1
libslirp
Fixed versions: 4.6.1-1
libslirp
Fixed versions: 4.6.1-1
qemu
Fixed versions: 1:4.1-2
qemu
Fixed versions: 1:4.1-2
qemu
Fixed versions: 1:4.1-2
Complete source record
{
"id": "e920c133cb89a654e12a3186b96ab83507ce93801d8d1db99f54d1658adc1ea5",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-3594",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2021-3594",
"summary": "An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp_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:DEBIAN-CVE-2021-3594",
"products": [
{
"name": {
"value": "libslirp",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.6.1-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
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},
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},
{
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{
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{
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{
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"affected_versions": []
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],
"severity": "low",
"structured": {
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"aliases": [
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],
"metrics": [
{
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"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N"
}
],
"affected": [
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{
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"package": {
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"purl": "pkg:deb/debian/libslirp?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
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"database_specific": {
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{
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"ecosystem": "Debian:13"
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"database_specific": {
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},
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},
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},
{
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"package": {
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"ecosystem": "Debian:13"
},
"database_specific": {
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},
"ecosystem_specific": {
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},
{
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"package": {
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},
"database_specific": {
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},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:03:29.537776902Z",
"provider": "osv",
"upstream": [
"CVE-2021-3594"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2021-3594"
]
},
"related_cves": [
{
"value": "CVE-2021-3594",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 421675,
"published_at": "2021-06-15T21:15:09.993+00:00"
}