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qemu — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-3750

A DMA reentrancy issue was found in the USB EHCI controller emulation of QEMU. EHCI does not verify if the Buffer Pointer overlaps with its MMIO region when it transfers the USB packets. Crafted content may be written to the controller's registers and trigger undesirable actions (such as reset) while the device is still transferring packets. This can ultimately lead to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition, or potentially execute arbitrary code within the context of the QEMU process on the host. This flaw affects QEMU versions before 7.0.0.

Products
qemu
Affected versions
Not specified
Fixed versions
1:7.0+dfsg-1
CVEs
CVE-2021-3750
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 00:50 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-3750

core-osv · Original source

Published 2 May 2022, 19:15 UTC

A DMA reentrancy issue was found in the USB EHCI controller emulation of QEMU. EHCI does not verify if the Buffer Pointer overlaps with its MMIO region when it transfers the USB packets. Crafted content may be written to the controller's registers and trigger undesirable actions (such as reset) while the device is still transferring packets. This can ultimately lead to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition, or potentially execute arbitrary code within the context of the QEMU process on the host. This flaw affects QEMU versions before 7.0.0.

osv:DEBIAN-CVE-2021-3750

qemu

Fixed versions: 1:7.0+dfsg-1

qemu

Fixed versions: 1:7.0+dfsg-1

qemu

Fixed versions: 1:7.0+dfsg-1

Complete source record
{
  "id": "4ca6251fc5b7962747adfdea9421e01279eb35ee42abe7408bc1294b34fe8be3",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-3750",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-3750",
    "summary": "A DMA reentrancy issue was found in the USB EHCI controller emulation of QEMU. EHCI does not verify if the Buffer Pointer overlaps with its MMIO region when it transfers the USB packets. Crafted content may be written to the controller's registers and trigger undesirable actions (such as reset) while the device is still transferring packets. This can ultimately lead to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition, or potentially execute arbitrary code within the context of the QEMU process on the host. This flaw affects QEMU versions before 7.0.0.",
    "evidence": "osv:DEBIAN-CVE-2021-3750",
    "products": [
      {
        "name": {
          "value": "qemu",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:7.0+dfsg-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "qemu",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:7.0+dfsg-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "qemu",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:7.0+dfsg-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-3750",
      "aliases": [
        "DEBIAN-CVE-2021-3750"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:7.0+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "qemu",
            "purl": "pkg:deb/debian/qemu?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-3750.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:7.0+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "qemu",
            "purl": "pkg:deb/debian/qemu?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-3750.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:7.0+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "qemu",
            "purl": "pkg:deb/debian/qemu?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-3750.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:03:50.104822859Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-3750"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-3750"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-3750",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 422409,
  "published_at": "2022-05-02T19:15:08.343+00:00"
}