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EUVD-2026-344371

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 07:56

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

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{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T07:56:05.714362+00:00",
  "id": "EUVD-2026-344371"
}

CVE-2021-47060 (GCVE-0-2021-47060)

Vulnerability from cvelistv5 – Published: 2024-02-29 22:37 – Updated: 2026-08-05 08:45

Title

KVM: Stop looking for coalesced MMIO zones if the bus is destroyed

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: Stop looking for coalesced MMIO zones if the bus is destroyed Abort the walk of coalesced MMIO zones if kvm_io_bus_unregister_dev() fails to allocate memory for the new instance of the bus. If it can't instantiate a new bus, unregister_dev() destroys all devices _except_ the target device. But, it doesn't tell the caller that it obliterated the bus and invoked the destructor for all devices that were on the bus. In the coalesced MMIO case, this can result in a deleted list entry dereference due to attempting to continue iterating on coalesced_zones after future entries (in the walk) have been deleted. Opportunistically add curly braces to the for-loop, which encompasses many lines but sneaks by without braces due to the guts being a single if statement.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

6 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-03-05 19:24 UTC

CWE

CWE-noinfo Not enough information

Assigner

Linux mitre root Scorecard

References

5 references

URL	Tags
https://git.kernel.org/stable/c/7d1bc32d6477ff96a…
https://git.kernel.org/stable/c/2a20592baff59c535…
https://git.kernel.org/stable/c/168e82f640ed1891a…
https://git.kernel.org/stable/c/50cbad42bfea8c052…
https://git.kernel.org/stable/c/5d3c4c79384af06e3…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 41b2ea7a6a11e2b1a7f2c29e1675a709a6b2b98d , < 7d1bc32d6477ff96a32695ea4be8144e4513ab2d (git) Affected: f65886606c2d3b562716de030706dfe1bea4ed5e , < 2a20592baff59c5351c5200ec667e1a2aa22af85 (git) Affected: f65886606c2d3b562716de030706dfe1bea4ed5e , < 168e82f640ed1891a700bdb43e37da354b2ab63c (git) Affected: f65886606c2d3b562716de030706dfe1bea4ed5e , < 50cbad42bfea8c052b7ca590bd4126cdc898713c (git) Affected: f65886606c2d3b562716de030706dfe1bea4ed5e , < 5d3c4c79384af06e3c8e25b7770b6247496b4417 (git) Affected: f0dfffce3f4ffd5f822568a4a6fb34c010e939d1 (git) Affected: 840e124f89a5127e7eb97ebf377f4b8ca745c070 (git) Affected: 40a023f681befd9b2862a3c16fb306a38b359ae5 (git) Affected: 19184bd06f488af62924ff1747614a8cb284ad63 (git) Affected: 68c125324b5e1d1d22805653735442923d896a1d (git) Affected: 5.4.66 , < 5.4.119 (semver) Affected: 4.4.238 , < 4.5 (semver) Affected: 4.9.238 , < 4.10 (semver) Affected: 4.14.200 , < 4.15 (semver) Affected: 4.19.148 , < 4.20 (semver) Affected: 5.8.10 , < 5.9 (semver)
Linux	Linux	Affected: 5.9 Unaffected: 0 , < 5.9 (semver) Unaffected: 5.4.119 , ≤ 5.4.* (semver) Unaffected: 5.10.37 , ≤ 5.10.* (semver) Unaffected: 5.11.21 , ≤ 5.11.* (semver) Unaffected: 5.12.4 , ≤ 5.12.* (semver) Unaffected: 5.13 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 6,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "NONE",
              "privilegesRequired": "HIGH",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H",
              "version": "3.1"
            }
          },
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              "content": {
                "id": "CVE-2021-47060",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-03-05T19:24:08.098826Z",
                "version": "2.0.3"
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              "type": "ssvc"
            }
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        "problemTypes": [
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                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-11-07T16:31:59.196Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:24:39.796Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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        "references": [
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          },
          {
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            "url": "https://git.kernel.org/stable/c/2a20592baff59c5351c5200ec667e1a2aa22af85"
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              "status": "affected",
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            },
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              "versionType": "git"
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              "status": "affected",
              "version": "5.4.66",
              "versionType": "semver"
            },
            {
              "lessThan": "4.5",
              "status": "affected",
              "version": "4.4.238",
              "versionType": "semver"
            },
            {
              "lessThan": "4.10",
              "status": "affected",
              "version": "4.9.238",
              "versionType": "semver"
            },
            {
              "lessThan": "4.15",
              "status": "affected",
              "version": "4.14.200",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "4.19.148",
              "versionType": "semver"
            },
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              "status": "affected",
              "version": "5.8.10",
              "versionType": "semver"
            }
          ]
        },
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          "product": "Linux",
          "programFiles": [
            "include/linux/kvm_host.h",
            "virt/kvm/coalesced_mmio.c",
            "virt/kvm/kvm_main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "5.9"
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              "version": "0",
              "versionType": "semver"
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                },
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Stop looking for coalesced MMIO zones if the bus is destroyed\n\nAbort the walk of coalesced MMIO zones if kvm_io_bus_unregister_dev()\nfails to allocate memory for the new instance of the bus.  If it can\u0027t\ninstantiate a new bus, unregister_dev() destroys all devices _except_ the\ntarget device.   But, it doesn\u0027t tell the caller that it obliterated the\nbus and invoked the destructor for all devices that were on the bus.  In\nthe coalesced MMIO case, this can result in a deleted list entry\ndereference due to attempting to continue iterating on coalesced_zones\nafter future entries (in the walk) have been deleted.\n\nOpportunistically add curly braces to the for-loop, which encompasses\nmany lines but sneaks by without braces due to the guts being a single\nif statement."
        }
      ],
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            "version": "3.1"
          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:L - The bug is reached via KVM_UNREGISTER_COALESCED_MMIO on a VM fd from kvm_vm_ioctl after open(\"/dev/kvm\")/KVM_CREATE_VM; it is a local host ioctl path, not network- or guest-MMIO-triggered.\nAC:L - The attacker fully controls registering multiple coalesced MMIO zones and the unregister ioctl, and can reliably force the GFP_KERNEL_ACCOUNT kmalloc failure (e.g., memcg/memory pressure) that triggers destruction of other bus devices and the UAF.\nPR:L - The ioctl path has no capable() check; access requires only /dev/kvm permissions (typically kvm-group membership), which is basic device access rather than real root/admin privileges that cannot be obtained without elevated rights.\nUI:N - The attacker triggers the vulnerability directly with their own KVM ioctls; no victim action is required.\nS:U - This is host userspace (VMM) corrupting host kernel state through the KVM ioctl interface, i.e. privilege escalation within the same security authority, not a guest-to-host escape via guest execution.\nC:H - The flaw is a use-after-free of kvm_coalesced_mmio_dev list entries (confirmed as UAF read by KASAN); freed objects can be reallocated/sprayed to obtain arbitrary kernel memory disclosure.\nI:H - UAF/double-free of IO bus device objects enables heap corruption and write primitives that can hijack kernel control flow, so integrity impact is high.\nA:H - Dereferencing deleted/freed list entries causes kernel oops/panic, and UAF paths are inherently crashable even without full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:45:46.354Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47060",
    "datePublished": "2024-02-29T22:37:34.885Z",
    "dateReserved": "2024-02-29T22:33:44.294Z",
    "dateUpdated": "2026-08-05T08:45:46.354Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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EUVD-2026-344371

CVE-2021-47060 (GCVE-0-2021-47060)

Tags

Sightings

Nomenclature

Related by attack behaviour