Medium
Security advisory
A heap buffer overflow was found in the floppy disk emulator of QEMU up to 6.0.0 (including). It could occur in fdctrl_transfer_handler() in hw/block/fdc.c while processing DMA read data transfers from the floppy drive to the guest system. A privileged guest user could use this flaw to crash the QEMU process on the host resulting in DoS scenario, or potential information leakage from the host memory.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-3507
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 05:51 UTC · Revision 1
Source evidence
A heap buffer overflow was found in the floppy disk emulator of QEMU up to 6.0.0 (including). It could occur in fdctrl_transfer_handler() in hw/block/fdc.c while processing DMA read data transfers from the floppy drive to the guest system. A privileged guest user could use this flaw to crash the QEMU process on the host resulting in DoS scenario, or potential information leakage from the host memory.
osv:CVE-2021-3507
Complete source record
{
"id": "7fba039851a816736990fb37a2bb4e031f8bda56d790356a1e5b995f5b3f1c0b",
"url": "https://osv.dev/vulnerability/CVE-2021-3507",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-3507",
"summary": "A heap buffer overflow was found in the floppy disk emulator of QEMU up to 6.0.0 (including). It could occur in fdctrl_transfer_handler() in hw/block/fdc.c while processing DMA read data transfers from the floppy drive to the guest system. A privileged guest user could use this flaw to crash the QEMU process on the host resulting in DoS scenario, or potential information leakage from the host memory.",
"evidence": "osv:CVE-2021-3507",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-3507",
"aliases": [
"CVE-2021-3507"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/qemu/qemu",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "609d7596524ab204ccd71ef42c9eee4c7c338ea4"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"last_affected": "6.0.0"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v6.0.0",
"v6.0.0-rc5",
"v6.0.0-rc4",
"v6.0.0-rc3",
"v6.0.0-rc2",
"v6.0.0-rc1",
"v6.0.0-rc0",
"v5.2.0",
"v5.2.0-rc4",
"v5.2.0-rc3",
"v5.2.0-rc2",
"v5.2.0-rc1",
"v5.2.0-rc0",
"v5.0.0",
"v5.1.0",
"v5.1.0-rc3",
"v5.1.0-rc2",
"v5.1.0-rc1",
"v5.1.0-rc0",
"v4.2.0",
"v5.0.0-rc4",
"v5.0.0-rc3",
"v5.0.0-rc2",
"v5.0.0-rc1",
"v5.0.0-rc0",
"v4.2.0-rc5",
"v4.2.0-rc4",
"v4.2.0-rc3",
"v4.2.0-rc2",
"v4.2.0-rc1",
"v4.2.0-rc0",
"v4.1.0",
"v4.0.0",
"v4.1.0-rc5",
"v4.1.0-rc4",
"v4.1.0-rc3",
"v4.1.0-rc2",
"v4.1.0-rc1",
"v4.1.0-rc0",
"v4.0.0-rc4",
"v4.0.0-rc3",
"v4.0.0-rc2",
"v4.0.0-rc1",
"v3.1.0",
"v4.0.0-rc0",
"v3.0.0",
"v3.1.0-rc5",
"v3.1.0-rc4",
"v3.1.0-rc3",
"v3.1.0-rc2",
"v3.1.0-rc1",
"v3.1.0-rc0",
"v3.0.0-rc4",
"v3.0.0-rc3",
"v3.0.0-rc2",
"v3.0.0-rc1",
"v3.0.0-rc0",
"v2.12.0",
"v2.12.0-rc4",
"v2.12.0-rc3",
"v2.12.0-rc2",
"v2.12.0-rc1",
"v2.12.0-rc0",
"v2.11.0",
"v2.11.0-rc5",
"v2.11.0-rc4",
"v2.11.0-rc3",
"v2.11.0-rc2",
"v2.11.0-rc1",
"v2.11.0-rc0",
"v2.10.0",
"v2.10.0-rc4",
"v2.10.0-rc3",
"v2.10.0-rc2",
"v2.10.0-rc1",
"v2.9.0",
"v2.10.0-rc0",
"v2.9.0-rc5",
"v2.9.0-rc4",
"v2.9.0-rc3",
"v2.9.0-rc2",
"v2.9.0-rc1",
"v2.8.0",
"v2.9.0-rc0",
"v2.8.0-rc4",
"v2.8.0-rc3",
"v2.8.0-rc2",
"v2.8.0-rc1",
"v2.8.0-rc0",
"v2.7.0",
"v2.7.0-rc5",
"v2.7.0-rc4",
"v2.7.0-rc3",
"v2.7.0-rc2",
"v2.6.0",
"v2.7.0-rc1",
"v2.7.0-rc0",
"v2.6.0-rc5",
"v2.6.0-rc4",
"v2.6.0-rc3",
"v2.6.0-rc2",
"v2.6.0-rc1",
"v2.6.0-rc0",
"v2.5.0",
"v2.5.0-rc4",
"v2.5.0-rc3",
"v2.5.0-rc2",
"v2.5.0-rc1",
"v2.5.0-rc0",
"v2.4.0",
"v2.4.0-rc4",
"v2.4.0-rc3",
"v2.3.0",
"v2.4.0-rc2",
"v2.4.0-rc1",
"v2.4.0-rc0",
"v2.3.0-rc4",
"v2.3.0-rc3",
"v2.3.0-rc2",
"v2.3.0-rc1",
"v2.3.0-rc0",
"v2.2.0",
"v2.2.0-rc3",
"v2.2.0-rc5",
"v2.2.0-rc4",
"v2.2.0-rc2",
"v2.2.0-rc1",
"v2.2.0-rc0",
"v2.1.0",
"v2.1.0-rc5",
"v2.1.0-rc4",
"v2.1.0-rc2",
"v2.1.0-rc3",
"v2.0.0",
"v2.1.0-rc1",
"v2.1.0-rc0",
"v2.0.0-rc3",
"v2.0.0-rc2",
"v2.0.0-rc1",
"v2.0.0-rc0",
"v1.7.0",
"v1.7.0-rc2",
"v1.7.0-rc1",
"v1.7.0-rc0",
"v1.6.0",
"v1.6.0-rc3",
"v1.6.0-rc2",
"v1.6.0-rc1",
"v1.6.0-rc0",
"v1.5.0",
"v1.5.0-rc3",
"v1.5.0-rc2",
"v1.5.0-rc1",
"v1.5.0-rc0",
"v1.4.0",
"v1.4.0-rc2",
"v1.4.0-rc1",
"v1.4.0-rc0",
"v1.3.0",
"v1.3.0-rc2",
"v1.3.0-rc1",
"v1.3.0-rc0",
"v1.2.0",
"v1.2.0-rc3",
"v1.2.0-rc2",
"v1.2.0-rc1",
"v1.2.0-rc0",
"v1.1.0",
"v1.1.0-rc4",
"v1.1.0-rc3",
"v1.1.0-rc2",
"v1.1-rc2",
"v1.1-rc1",
"v1.1-rc0",
"v1.0",
"v1.0-rc4",
"v1.0-rc3",
"v1.0-rc2",
"v1.0-rc1",
"v1.0-rc0",
"v0.14.0-rc0",
"v0.13.0-rc0",
"v0.12.0-rc0",
"v0.11.0-rc0",
"v0.5.0",
"v0.4.4",
"v0.4.3",
"v0.4.2",
"v0.4.1",
"v0.4.0",
"v0.3.0",
"v0.2.0",
"v0.1.6",
"v0.1.5",
"v0.1.4",
"v0.1.3",
"v0.1.1",
"v0.1.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3507.json"
}
},
{
"ranges": [
{
"repo": "https://gitlab.com/qemu-project/qemu",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "609d7596524ab204ccd71ef42c9eee4c7c338ea4"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"last_affected": "6.0.0"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v6.0.0",
"v6.0.0-rc5",
"v6.0.0-rc4",
"v6.0.0-rc3",
"v6.0.0-rc2",
"v6.0.0-rc1",
"v6.0.0-rc0",
"v5.2.0",
"v5.2.0-rc4",
"v5.2.0-rc3",
"v5.2.0-rc2",
"v5.2.0-rc1",
"v5.2.0-rc0",
"v5.0.0",
"v5.1.0",
"v5.1.0-rc3",
"v5.1.0-rc2",
"v5.1.0-rc1",
"v5.1.0-rc0",
"v4.2.0",
"v5.0.0-rc4",
"v5.0.0-rc3",
"v5.0.0-rc2",
"v5.0.0-rc1",
"v5.0.0-rc0",
"v4.2.0-rc5",
"v4.2.0-rc4",
"v4.2.0-rc3",
"v4.2.0-rc2",
"v4.2.0-rc1",
"v4.2.0-rc0",
"v4.1.0",
"v4.0.0",
"v4.1.0-rc5",
"v4.1.0-rc4",
"v4.1.0-rc3",
"v4.1.0-rc2",
"v4.1.0-rc1",
"v4.1.0-rc0",
"v4.0.0-rc4",
"v4.0.0-rc3",
"v4.0.0-rc2",
"v4.0.0-rc1",
"v3.1.0",
"v4.0.0-rc0",
"v3.0.0",
"v3.1.0-rc5",
"v3.1.0-rc4",
"v3.1.0-rc3",
"v3.1.0-rc2",
"v3.1.0-rc1",
"v3.1.0-rc0",
"v3.0.0-rc4",
"v3.0.0-rc3",
"v3.0.0-rc2",
"v3.0.0-rc1",
"v3.0.0-rc0",
"v2.12.0",
"v2.12.0-rc4",
"v2.12.0-rc3",
"v2.12.0-rc2",
"v2.12.0-rc1",
"v2.12.0-rc0",
"v2.11.0",
"v2.11.0-rc5",
"v2.11.0-rc4",
"v2.11.0-rc3",
"v2.11.0-rc2",
"v2.11.0-rc1",
"v2.11.0-rc0",
"v2.10.0",
"v2.10.0-rc4",
"v2.10.0-rc3",
"v2.10.0-rc2",
"v2.10.0-rc1",
"v2.9.0",
"v2.10.0-rc0",
"v2.9.0-rc5",
"v2.9.0-rc4",
"v2.9.0-rc3",
"v2.9.0-rc2",
"v2.9.0-rc1",
"v2.8.0",
"v2.9.0-rc0",
"v2.8.0-rc4",
"v2.8.0-rc3",
"v2.8.0-rc2",
"v2.8.0-rc1",
"v2.8.0-rc0",
"v2.7.0",
"v2.7.0-rc5",
"v2.7.0-rc4",
"v2.7.0-rc3",
"v2.7.0-rc2",
"v2.6.0",
"v2.7.0-rc1",
"v2.7.0-rc0",
"v2.6.0-rc5",
"v2.6.0-rc4",
"v2.6.0-rc3",
"v2.6.0-rc2",
"v2.6.0-rc1",
"v2.6.0-rc0",
"v2.5.0",
"v2.5.0-rc4",
"v2.5.0-rc3",
"v2.5.0-rc2",
"v2.5.0-rc1",
"v2.5.0-rc0",
"v2.4.0",
"v2.4.0-rc4",
"v2.4.0-rc3",
"v2.3.0",
"v2.4.0-rc2",
"v2.4.0-rc1",
"v2.4.0-rc0",
"v2.3.0-rc4",
"v2.3.0-rc3",
"v2.3.0-rc2",
"v2.3.0-rc1",
"v2.3.0-rc0",
"v2.2.0",
"v2.2.0-rc3",
"v2.2.0-rc5",
"v2.2.0-rc4",
"v2.2.0-rc2",
"v2.2.0-rc1",
"v2.2.0-rc0",
"v2.1.0",
"v2.1.0-rc5",
"v2.1.0-rc4",
"v2.1.0-rc2",
"v2.1.0-rc3",
"v2.0.0",
"v2.1.0-rc1",
"v2.1.0-rc0",
"v2.0.0-rc3",
"v2.0.0-rc2",
"v2.0.0-rc1",
"v2.0.0-rc0",
"v1.7.0",
"v1.7.0-rc2",
"v1.7.0-rc1",
"v1.7.0-rc0",
"v1.6.0",
"v1.6.0-rc3",
"v1.6.0-rc2",
"v1.6.0-rc1",
"v1.6.0-rc0",
"v1.5.0",
"v1.5.0-rc3",
"v1.5.0-rc2",
"v1.5.0-rc1",
"v1.5.0-rc0",
"v1.4.0",
"v1.4.0-rc2",
"v1.4.0-rc1",
"v1.4.0-rc0",
"v1.3.0",
"v1.3.0-rc2",
"v1.3.0-rc1",
"v1.3.0-rc0",
"v1.2.0",
"v1.2.0-rc3",
"v1.2.0-rc2",
"v1.2.0-rc1",
"v1.2.0-rc0",
"v1.1.0",
"v1.1.0-rc4",
"v1.1.0-rc3",
"v1.1.0-rc2",
"v1.1-rc2",
"v1.1-rc1",
"v1.1-rc0",
"v1.0",
"v1.0-rc4",
"v1.0-rc3",
"v1.0-rc2",
"v1.0-rc1",
"v1.0-rc0",
"v0.14.0-rc0",
"v0.13.0-rc0",
"v0.12.0-rc0",
"v0.11.0-rc0",
"v0.5.0",
"v0.4.4",
"v0.4.3",
"v0.4.2",
"v0.4.1",
"v0.4.0",
"v0.3.0",
"v0.2.0",
"v0.1.6",
"v0.1.5",
"v0.1.4",
"v0.1.3",
"v0.1.1",
"v0.1.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3507.json"
}
}
],
"modified": "2026-10-24T10:30:33.472313108Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html",
"https://security.netapp.com/advisory/ntap-20210528-0005/",
"https://bugzilla.redhat.com/show_bug.cgi?id=1951118"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "10.0"
},
{
"last_affected": "10.0"
}
],
"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-2021-3507",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 433294,
"published_at": "2021-05-06T16:15:07.547+00:00"
}