CVE-2026-93827 (GCVE-0-2026-93827)

Vulnerability from cvelistv5 – Published: 2026-09-24 16:03 – Updated: 2026-09-25 05:10
VLAI
Title
virtio-fs: avoid double-free on failed queue setup
Summary
In the Linux kernel, the following vulnerability has been resolved: virtio-fs: avoid double-free on failed queue setup virtio_fs_setup_vqs() allocates fs->vqs and fs->mq_map before calling virtio_find_vqs(). If virtio_find_vqs() fails, the error path frees both pointers and returns an error to virtio_fs_probe(). virtio_fs_probe() then drops the last kobject reference, and virtio_fs_ktype_release() frees fs->vqs and fs->mq_map again. This leaves dangling pointers in struct virtio_fs and can trigger a double-free during probe failure cleanup. Set fs->vqs and fs->mq_map to NULL immediately after kfree() in the virtio_fs_setup_vqs() error path so that the later kobject release sees an uninitialized state and kfree(NULL) becomes harmless. This can be reproduced when a broken virtio-fs device advertises more request queues than the transport actually provides. In that case virtio_find_vqs() fails while setting up the extra queue, and the probe path reaches the double-free cleanup sequence.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3fbc5ee776fefbc6ea34d2518f1f5f90aa2e1dad (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 20ef4739b329bb09cff11dd2458795a50674658e (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6af3330ec5d5fb8c06c04eb520a71cf73ea5a765 (git)
Affected: 0 , < 6.12.111 (semver)
Affected: 0 , < 6.18.53 (semver)
guessed Create a notification for this product.
Linux Linux Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/virtio_fs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3fbc5ee776fefbc6ea34d2518f1f5f90aa2e1dad",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "20ef4739b329bb09cff11dd2458795a50674658e",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6af3330ec5d5fb8c06c04eb520a71cf73ea5a765",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6.12.111",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18.53",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/virtio_fs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio-fs: avoid double-free on failed queue setup\n\nvirtio_fs_setup_vqs() allocates fs-\u003evqs and fs-\u003emq_map before calling\nvirtio_find_vqs(). If virtio_find_vqs() fails, the error path frees both\npointers and returns an error to virtio_fs_probe().\n\nvirtio_fs_probe() then drops the last kobject reference, and\nvirtio_fs_ktype_release() frees fs-\u003evqs and fs-\u003emq_map again. This leaves\ndangling pointers in struct virtio_fs and can trigger a double-free during\nprobe failure cleanup.\n\nSet fs-\u003evqs and fs-\u003emq_map to NULL immediately after kfree() in the\nvirtio_fs_setup_vqs() error path so that the later kobject release sees an\nuninitialized state and kfree(NULL) becomes harmless.\n\nThis can be reproduced when a broken virtio-fs device advertises more\nrequest queues than the transport actually provides. In that case\nvirtio_find_vqs() fails while setting up the extra queue, and the probe\npath reaches the double-free cleanup sequence."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The triggering field is virtio_fs_config.num_request_queues, read by virtio_cread_le() in virtio_fs_setup_vqs() from virtio_fs_probe() via virtio_dev_probe() after virtio_pci_probe()/register_virtio_device() binds a VIRTIO_ID_FS device; those bytes come from local PCI/MMIO/vDPA config space, not a network protocol message.\nAC:L - A device that advertises more request queues than it exposes makes virtio_find_vqs()-\u003evp_setup_vq() fail (-EINVAL when index \u003e= vp_modern_get_num_queues(), or -ENOENT on queue size 0); virtio_fs_setup_vqs() then kfree\u0027s fs-\u003evqs and fs-\u003emq_map and virtio_fs_probe() always kobject_put()s into the second free, with no race.\nPR:N - virtio_fs_probe()/virtio_fs_setup_vqs() have no capable() or credential check; MODULE_DEVICE_TABLE(virtio, id_table) autoloads virtiofs and virtio_dev_probe() binds a VIRTIO_ID_FS device at enumeration or hotplug, so a malicious virtio-fs backend needs no account on the guest.\nUI:N - The double-free runs in the probe error path (virtio_fs_setup_vqs() failure, then kobject_put() into virtio_fs_ktype_release()) when the device appears; virtio_fs_add_instance() and a virtiofs mount are never reached, so no victim must mount or open anything.\nS:U - virtio_fs_ktype_release() double-frees the guest kernel kmalloc objects fs-\u003evqs and fs-\u003emq_map; that is device-to-guest heap corruption inside the same guest kernel, not a write into host virtiofsd or a KVM/IOMMU escape.\nC:H - kfree(fs-\u003evqs) and kfree(fs-\u003emq_map) in virtio_fs_setup_vqs() leave dangling pointers that virtio_fs_ktype_release() frees again; a slab double-free of that virtio_fs_vq array and per-CPU mq_map lets those objects overlap so the attacker can read adjacent kernel heap.\nI:H - The same second kfree of fs-\u003evqs and fs-\u003emq_map corrupts the SLUB freelist for those kmalloc objects and is an arbitrary-free primitive, enabling heap overwrite and control-flow hijack in the guest kernel.\nA:H - Double-free of fs-\u003evqs and fs-\u003emq_map in virtio_fs_ktype_release() after virtio_find_vqs() fails oopses or panics the guest during probe cleanup (KASAN invalid-free, SLUB poisoned-freelist BUG, or panic_on_oops)."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T05:10:22.640Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3fbc5ee776fefbc6ea34d2518f1f5f90aa2e1dad"
        },
        {
          "url": "https://git.kernel.org/stable/c/20ef4739b329bb09cff11dd2458795a50674658e"
        },
        {
          "url": "https://git.kernel.org/stable/c/6af3330ec5d5fb8c06c04eb520a71cf73ea5a765"
        }
      ],
      "title": "virtio-fs: avoid double-free on failed queue setup",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93827",
    "datePublished": "2026-09-24T16:03:05.795Z",
    "dateReserved": "2026-09-18T17:59:28.792Z",
    "dateUpdated": "2026-09-25T05:10:22.640Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/fuse/virtio_fs.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "3fbc5ee776fefbc6ea34d2518f1f5f90aa2e1dad",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "20ef4739b329bb09cff11dd2458795a50674658e",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6af3330ec5d5fb8c06c04eb520a71cf73ea5a765",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6.12.111",
                    "status": "affected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "6.18.53",
                    "status": "affected",
                    "version": "0",
                    "versionType": "semver"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/fuse/virtio_fs.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.111",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.53",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.2",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio-fs: avoid double-free on failed queue setup\n\nvirtio_fs_setup_vqs() allocates fs-\u003evqs and fs-\u003emq_map before calling\nvirtio_find_vqs(). If virtio_find_vqs() fails, the error path frees both\npointers and returns an error to virtio_fs_probe().\n\nvirtio_fs_probe() then drops the last kobject reference, and\nvirtio_fs_ktype_release() frees fs-\u003evqs and fs-\u003emq_map again. This leaves\ndangling pointers in struct virtio_fs and can trigger a double-free during\nprobe failure cleanup.\n\nSet fs-\u003evqs and fs-\u003emq_map to NULL immediately after kfree() in the\nvirtio_fs_setup_vqs() error path so that the later kobject release sees an\nuninitialized state and kfree(NULL) becomes harmless.\n\nThis can be reproduced when a broken virtio-fs device advertises more\nrequest queues than the transport actually provides. In that case\nvirtio_find_vqs() fails while setting up the extra queue, and the probe\npath reaches the double-free cleanup sequence."
          }
        ],
        "id": "CVE-2026-93827",
        "lastModified": "2026-09-25T05:17:04.170",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 8.4,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.5,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-24T17:17:16.410",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/20ef4739b329bb09cff11dd2458795a50674658e"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/3fbc5ee776fefbc6ea34d2518f1f5f90aa2e1dad"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/6af3330ec5d5fb8c06c04eb520a71cf73ea5a765"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-09-24T23:47:05Z",
      "cve": "CVE-2026-93827",
      "id": "CVE-2026-93827",
      "initial_release_date": "2026-09-24T23:47:05Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-93827",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-93827.json",
      "version": "2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.