Low
Security advisory
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the tftp_input() function and could occur while processing a udp packet that is smaller than the size of the 'tftp_t' 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-2021-3595
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 07:05 UTC · Revision 1
Source evidence
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the tftp_input() function and could occur while processing a udp packet that is smaller than the size of the 'tftp_t' 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-2021-3595
Complete source record
{
"id": "03fd81f20b4e3d96d6cb340a83f81d5319e5db6901b38d2fb0e97bf7f3357260",
"url": "https://osv.dev/vulnerability/CVE-2021-3595",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-3595",
"summary": "An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the tftp_input() function and could occur while processing a udp packet that is smaller than the size of the 'tftp_t' 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-2021-3595",
"products": [],
"severity": "low",
"structured": {
"id": "CVE-2021-3595",
"aliases": [
"CVE-2021-3595"
],
"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": [
{
"introduced": "0"
},
{
"fixed": "6ef66db79938d763212320c1b64bc562c23d25a8"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:libslirp_project:libslirp:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "4.6.0"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v4.3.1",
"v4.3.0",
"v4.2.0",
"v4.1.0",
"v4.0.0",
"v4.0.0-rc0",
"v3.1.0-rc5",
"v3.1.0-rc4",
"v3.1.0-rc3",
"v3.1.0-rc2",
"v3.1.0-rc1",
"v3.1.0",
"v3.1.0-rc0",
"v3.0.0-rc4",
"v3.0.0",
"v3.0.0-rc3",
"v3.0.0-rc2",
"v3.0.0-rc1",
"v3.0.0-rc0",
"v2.12.1",
"v2.12.0-rc4",
"v2.12.0-rc3",
"v2.12.0-rc2",
"v2.12.0-rc1",
"v2.12.0-rc0",
"v2.12.0",
"v2.11.2",
"v2.11.1",
"v2.11.0-rc5",
"v2.11.0-rc4",
"v2.11.0-rc3",
"v2.11.0-rc2",
"v2.11.0-rc1",
"v2.11.0",
"v2.11.0-rc0",
"v2.10.0-rc4",
"v2.10.0-rc3",
"v2.10.0-rc2",
"v2.10.0",
"v2.10.0-rc1",
"v2.10.0-rc0",
"v2.9.0-rc5",
"v2.9.0-rc4",
"v2.9.0-rc3",
"v2.9.0",
"v2.9.0-rc2",
"v2.9.0-rc1",
"v2.9.0-rc0",
"v2.8.1.1",
"v2.8.1",
"v2.8.0-rc4",
"v2.8.0-rc3",
"v2.8.0-rc2",
"v2.8.0-rc1",
"v2.8.0-rc0",
"v2.8.0",
"v2.7.0-rc5",
"v2.7.0-rc4",
"v2.7.0-rc3",
"v2.7.0",
"v2.7.0-rc2",
"v2.7.0-rc1",
"v2.7.0-rc0",
"v2.6.0-rc5",
"v2.6.0-rc4",
"v2.6.0",
"v2.6.0-rc3",
"v2.6.0-rc2",
"v2.6.0-rc1",
"v2.6.0-rc0",
"v2.5.1.1",
"v2.5.1",
"v2.5.0-rc4",
"v2.5.0-rc3",
"v2.5.0-rc2",
"v2.5.0-rc1",
"v2.5.0-rc0",
"v2.5.0",
"v2.4.0.1",
"v2.4.0-rc4",
"v2.4.0-rc3",
"v2.4.0-rc2",
"v2.4.0-rc1",
"v2.4.0-rc0",
"v2.4.0",
"v2.3.1",
"v2.3.0-rc4",
"v2.3.0-rc3",
"v2.3.0-rc2",
"v2.3.0-rc1",
"v2.3.0-rc0",
"v2.3.0",
"v2.2.1",
"v2.2.0-rc5",
"v2.2.0-rc4",
"v2.2.0-rc3",
"v2.2.0-rc2",
"v2.2.0-rc1",
"v2.2.0-rc0",
"v2.2.0",
"v2.1.1",
"v2.1.0-rc5",
"v2.1.0-rc4",
"v2.1.0-rc3",
"v2.1.0-rc2",
"v2.1.0-rc1",
"v2.1.0-rc0",
"v2.1.0",
"v2.0.2",
"v2.0.1",
"v2.0.0-rc3",
"v2.0.0-rc2",
"v2.0.0-rc1",
"v2.0.0",
"v2.0.0-rc0",
"v1.7.2",
"v1.7.1",
"v1.7.0-rc2",
"v1.7.0-rc1",
"v1.7.0-rc0",
"v1.7.0",
"v1.6.2",
"v1.6.1",
"v1.6.0-rc3",
"v1.6.0-rc2",
"v1.6.0-rc1",
"v1.6.0-rc0",
"v1.6.0",
"v1.5.3",
"v1.5.2",
"v1.5.1",
"v1.5.0-rc3",
"v1.5.0-rc2",
"v1.5.0-rc1",
"v1.5.0-rc0",
"v1.5.0",
"v1.4.0-rc2",
"v1.4.0-rc1",
"v1.4.0-rc0",
"v1.4.0",
"v1.3.1",
"v1.3.0-rc2",
"v1.3.0-rc1",
"v1.3.0-rc0",
"v1.3.0",
"v1.2.0-rc3",
"v1.2.0-rc2",
"v1.2.0-rc1",
"v1.2.0-rc0",
"v1.2.0",
"v1.1.2",
"v1.1.1",
"v1.1.0-rc4",
"v1.1.0",
"v1.1.0-rc3",
"v1.1.0-rc2",
"v1.1-rc2",
"v1.1-rc1",
"v1.1-rc0",
"v1.0.1",
"v1.0-rc4",
"v1.0-rc3",
"v1.0-rc2",
"v1.0-rc1",
"v1.0-rc0",
"v1.0",
"v0.15.1",
"v0.15.0-rc2",
"v0.15.0-rc1",
"v0.15.0",
"v0.15.0-rc0",
"v0.14.0-rc1",
"v0.14.0-rc0",
"v0.13.0-rc3",
"v0.13.0-rc2",
"v0.13.0-rc1",
"v0.13.0-rc0",
"v0.13.0",
"v0.12.1",
"v0.12.0-rc2",
"v0.12.0-rc1",
"v0.12.0-rc0",
"v0.12.0",
"v0.11.0-rc0",
"v0.10.6",
"v0.10.5",
"v0.10.4",
"v0.10.3",
"v0.10.2",
"v0.10.1",
"v0.10.0",
"release_0_10_2",
"release_0_10_1",
"release_0_10_0",
"v0.9.1",
"release_0_9_1",
"v0.9.0",
"release_0_9_0",
"v0.8.2",
"release_0_8_2",
"v0.8.1",
"release_0_8_1",
"v0.7.1",
"release_0_7_1",
"v0.7.0",
"release_0_7_0",
"v0.6.1",
"release_0_6_1",
"v0.6.0",
"release_0_6_0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3595.json"
}
}
],
"modified": "2026-10-24T10:30:48.508716068Z",
"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/2021/09/msg00000.html",
"https://security.gentoo.org/glsa/202107-44",
"https://security.netapp.com/advisory/ntap-20210805-0004/",
"https://bugzilla.redhat.com/show_bug.cgi?id=1970489"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:a:libslirp_project:libslirp:*:*:*:*:*:*:*:*"
],
"vendor_product": "libslirp_project:libslirp",
"extracted_events": [
{
"range": [
{
"fixed": "4.6.0"
}
],
"source": "CPE_RANGE"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
"cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*"
],
"vendor_product": "fedoraproject:fedora",
"extracted_events": [
{
"range": [
{
"introduced": "33"
},
{
"last_affected": "33"
},
{
"introduced": "34"
},
{
"last_affected": "34"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:*"
],
"vendor_product": "redhat:enterprise_linux",
"extracted_events": [
{
"range": [
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
},
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2021-3595",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 436781,
"published_at": "2021-06-15T21:15:10.643+00:00"
}