CVE-2026-74713 (GCVE-0-2026-74713)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-10-16 19:16
VLAI
Title
vhost_iotlb: bound map allocation in add_range
Summary
In the Linux kernel, the following vulnerability has been resolved: vhost_iotlb: bound map allocation in add_range vhost_iotlb_add_range_ctx() only retires an old entry when the table has a non-zero limit, has exactly reached that limit and has VHOST_IOTLB_FLAG_RETIRE set. Non-retiring tables can keep allocating entries after reaching their configured limit. Existing vhost devices allocate their IOTLB with max_iotlb_entries from vhost.c, which defaults to 2048 and is tunable by module parameter. Use the caller-provided limit at the allocation point instead of adding a separate default in the common IOTLB helper, and reject non-positive values in vhost paths that can report an error. Other vhost IOTLB users should not create zero-limit tables when entries can be populated from userspace or guest-controlled requests. Add caller-side max_iotlb_entries parameters for mlx5 vDPA, VDUSE and vhost-vDPA. Reject non-positive VDUSE and vhost-vDPA values, and require at least two entries for vdpa_sim and mlx5 vDPA paths that install full-range mappings, since those mappings are split into two IOTLB entries. Handle full-range mappings in the common helper by checking that the IOTLB can hold both split entries before inserting the first half. This avoids returning an error after leaving a half mapping behind. When the table is full, keep the existing retire behavior for retiring tables and return -ENOSPC for non-retiring tables. Reuse the retired map node instead of freeing it and allocating a replacement, so a stream of IOTLB updates cannot keep forcing GFP_ATOMIC allocations after the table has reached its limit. If a zero-limit IOTLB still reaches the common helper, treat it as a configuration error and return -EINVAL. I found this bug myself, though the patch was written with AI assistance.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-16 19:15 UTC
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6666 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0bbe30668d89ec8a309f28ced6d092c90fb23e8c , < b57164cdddb46924ff9fa191b727ca097744de88 (git)
Affected: 0bbe30668d89ec8a309f28ced6d092c90fb23e8c , < ae128dd19040ee06a4f8143c7ced4d18080d7a9a (git)
Affected: 0bbe30668d89ec8a309f28ced6d092c90fb23e8c , < 1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94 (git)
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Linux Linux Affected: 5.7
Unaffected: 0 , < 5.7 (semver)
Unaffected: 6.18.57 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost_iotlb: bound map allocation in add_range\n\nvhost_iotlb_add_range_ctx() only retires an old entry when the table\nhas a non-zero limit, has exactly reached that limit and has\nVHOST_IOTLB_FLAG_RETIRE set. Non-retiring tables can keep allocating\nentries after reaching their configured limit.\n\nExisting vhost devices allocate their IOTLB with max_iotlb_entries from\nvhost.c, which defaults to 2048 and is tunable by module parameter. Use\nthe caller-provided limit at the allocation point instead of adding a\nseparate default in the common IOTLB helper, and reject non-positive\nvalues in vhost paths that can report an error.\n\nOther vhost IOTLB users should not create zero-limit tables when entries\ncan be populated from userspace or guest-controlled requests. Add\ncaller-side max_iotlb_entries parameters for mlx5 vDPA, VDUSE and\nvhost-vDPA. Reject non-positive VDUSE and vhost-vDPA values, and require\nat least two entries for vdpa_sim and mlx5 vDPA paths that install\nfull-range mappings, since those mappings are split into two IOTLB\nentries.\n\nHandle full-range mappings in the common helper by checking that the\nIOTLB can hold both split entries before inserting the first half. This\navoids returning an error after leaving a half mapping behind.\n\nWhen the table is full, keep the existing retire behavior for retiring\ntables and return -ENOSPC for non-retiring tables. Reuse the retired map\nnode instead of freeing it and allocating a replacement, so a stream of\nIOTLB updates cannot keep forcing GFP_ATOMIC allocations after the table\nhas reached its limit. If a zero-limit IOTLB still reaches the common\nhelper, treat it as a configuration error and return -EINVAL.\n\nI found this bug myself, though the patch was written with AI assistance."
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            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nvhost_iotlb: asignaci\u00f3n de mapa limitada en add_range\n\nvhost_iotlb_add_range_ctx() solo retira una entrada antigua cuando la tabla tiene un l\u00edmite no nulo, ha alcanzado exactamente ese l\u00edmite y tiene VHOST_IOTLB_FLAG_RETIRE establecido. Las tablas que no retiran pueden seguir asignando entradas despu\u00e9s de alcanzar su l\u00edmite configurado.\n\nLos dispositivos vhost existentes asignan su IOTLB con max_iotlb_entries de vhost.c, que por defecto es 2048 y es configurable mediante un par\u00e1metro de m\u00f3dulo. Utilice el l\u00edmite proporcionado por el llamador en el punto de asignaci\u00f3n en lugar de a\u00f1adir un valor predeterminado separado en el asistente IOTLB com\u00fan, y rechace los valores no positivos en las rutas vhost que pueden informar un error.\n\nOtros usuarios de IOTLB de vhost no deben crear tablas de l\u00edmite cero cuando las entradas pueden ser pobladas desde el espacio de usuario o solicitudes controladas por el invitado. A\u00f1ada par\u00e1metros max_iotlb_entries del lado del llamador para mlx5 vDPA, VDUSE y vhost-vDPA. Rechace los valores no positivos de VDUSE y vhost-vDPA, y requiera al menos dos entradas para las rutas vdpa_sim y mlx5 vDPA que instalan mapeos de rango completo, ya que esos mapeos se dividen en dos entradas IOTLB.\n\nManeje los mapeos de rango completo en el asistente com\u00fan verificando que el IOTLB puede contener ambas entradas divididas antes de insertar la primera mitad. Esto evita devolver un error despu\u00e9s de dejar un mapeo a medias.\n\nCuando la tabla est\u00e1 llena, mantenga el comportamiento de retiro existente para las tablas que retiran y devuelva -ENOSPC para las tablas que no retiran. Reutilice el nodo de mapa retirado en lugar de liberarlo y asignar un reemplazo, para que un flujo de actualizaciones de IOTLB no pueda seguir forzando asignaciones GFP_ATOMIC despu\u00e9s de que la tabla haya alcanzado su l\u00edmite. Si un IOTLB de l\u00edmite cero a\u00fan llega al asistente com\u00fan, tr\u00e1telo como un error de configuraci\u00f3n y devuelva -EINVAL.\n\nEncontr\u00e9 este error yo mismo, aunque el parche fue escrito con asistencia de IA."
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                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-10-16T19:15:21.643384Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-10-16T19:15:22.456Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "drivers/vdpa/mlx5/core/mlx5_vdpa.h",
                "drivers/vdpa/mlx5/core/mr.c",
                "drivers/vdpa/mlx5/core/resources.c",
                "drivers/vdpa/vdpa_sim/vdpa_sim.c",
                "drivers/vdpa/vdpa_user/iova_domain.c",
                "drivers/vhost/iotlb.c",
                "drivers/vhost/vdpa.c",
                "drivers/vhost/vhost.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "b57164cdddb46924ff9fa191b727ca097744de88",
                  "status": "affected",
                  "version": "0bbe30668d89ec8a309f28ced6d092c90fb23e8c",
                  "versionType": "git"
                },
                {
                  "lessThan": "ae128dd19040ee06a4f8143c7ced4d18080d7a9a",
                  "status": "affected",
                  "version": "0bbe30668d89ec8a309f28ced6d092c90fb23e8c",
                  "versionType": "git"
                },
                {
                  "lessThan": "1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94",
                  "status": "affected",
                  "version": "0bbe30668d89ec8a309f28ced6d092c90fb23e8c",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "drivers/vdpa/mlx5/core/mlx5_vdpa.h",
                "drivers/vdpa/mlx5/core/mr.c",
                "drivers/vdpa/mlx5/core/resources.c",
                "drivers/vdpa/vdpa_sim/vdpa_sim.c",
                "drivers/vdpa/vdpa_user/iova_domain.c",
                "drivers/vhost/iotlb.c",
                "drivers/vhost/vdpa.c",
                "drivers/vhost/vhost.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "5.7"
                },
                {
                  "lessThan": "5.7",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.18.*",
                  "status": "unaffected",
                  "version": "6.18.57",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "7.1.*",
                  "status": "unaffected",
                  "version": "7.1.9",
                  "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": "6.18.57",
                      "versionStartIncluding": "5.7",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "7.1.9",
                      "versionStartIncluding": "5.7",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "7.2",
                      "versionStartIncluding": "5.7",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost_iotlb: bound map allocation in add_range\n\nvhost_iotlb_add_range_ctx() only retires an old entry when the table\nhas a non-zero limit, has exactly reached that limit and has\nVHOST_IOTLB_FLAG_RETIRE set. Non-retiring tables can keep allocating\nentries after reaching their configured limit.\n\nExisting vhost devices allocate their IOTLB with max_iotlb_entries from\nvhost.c, which defaults to 2048 and is tunable by module parameter. Use\nthe caller-provided limit at the allocation point instead of adding a\nseparate default in the common IOTLB helper, and reject non-positive\nvalues in vhost paths that can report an error.\n\nOther vhost IOTLB users should not create zero-limit tables when entries\ncan be populated from userspace or guest-controlled requests. Add\ncaller-side max_iotlb_entries parameters for mlx5 vDPA, VDUSE and\nvhost-vDPA. Reject non-positive VDUSE and vhost-vDPA values, and require\nat least two entries for vdpa_sim and mlx5 vDPA paths that install\nfull-range mappings, since those mappings are split into two IOTLB\nentries.\n\nHandle full-range mappings in the common helper by checking that the\nIOTLB can hold both split entries before inserting the first half. This\navoids returning an error after leaving a half mapping behind.\n\nWhen the table is full, keep the existing retire behavior for retiring\ntables and return -ENOSPC for non-retiring tables. Reuse the retired map\nnode instead of freeing it and allocating a replacement, so a stream of\nIOTLB updates cannot keep forcing GFP_ATOMIC allocations after the table\nhas reached its limit. If a zero-limit IOTLB still reaches the common\nhelper, treat it as a configuration error and return -EINVAL.\n\nI found this bug myself, though the patch was written with AI assistance."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:L - The flaw is reached via local VHOST_IOTLB_UPDATE writes on /dev/vhost-* or /dev/vhost-vdpa char devices, or when a KVM guest drives virtio IOTLB misses that the VMM resolves through vhost; it is not triggered by remote network packets.\nAC:L - An attacker reliably floods distinct IOTLB mappings by repeatedly issuing VHOST_IOTLB_UPDATE messages or provoking guest IOTLB misses; no race, rare configuration, or attacker-uncontrollable memory layout is required once vhost IOTLB is active.\nPR:N - A malicious KVM guest can provoke unbounded IOTLB growth through normal virtio IOTLB-miss handling without any host credentials; a host attacker holding the vhost-vdpa/vhost device node also needs no capabilities beyond device access.\nUI:N - Exploitation requires no victim interaction beyond the VM or vhost device already being in use; the attacker programmatically drives the IOTLB update stream in a tight loop.\nS:C - In cloud/KVM deployments, an unprivileged guest VM causes unbounded host-kernel GFP_ATOMIC allocations in vhost_iotlb_add_range_ctx(), crossing the VM/host security boundary to deny service on the hypervisor.\nC:N - The bug causes only unbounded kmalloc of vhost_iotlb_map structures without out-of-bounds access, use-after-free, or information disclosure; successful exploitation does not read kernel memory.\nI:N - No memory corruption or arbitrary write occurs; impact is limited to kernel memory consumption and does not modify data or enable code execution through the allocation flaw itself.\nA:H - Unbounded IOTLB entry allocation or perpetual GFP_ATOMIC kmalloc when tables are at capacity exhausts kernel memory/atomic reserves, causing host OOM, kernel panics, or complete hypervisor denial of service."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-10-15T10:09:21.582Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/b57164cdddb46924ff9fa191b727ca097744de88"
            },
            {
              "url": "https://git.kernel.org/stable/c/ae128dd19040ee06a4f8143c7ced4d18080d7a9a"
            },
            {
              "url": "https://git.kernel.org/stable/c/1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94"
            }
          ],
          "title": "vhost_iotlb: bound map allocation in add_range",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2026-74713",
        "datePublished": "2026-08-22T15:33:09.028Z",
        "dateReserved": "2026-08-15T05:44:03.928Z",
        "dateUpdated": "2026-10-16T19:16:11.209Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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