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

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-25 05:41
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
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0bbe30668d89ec8a309f28ced6d092c90fb23e8c , < ae128dd19040ee06a4f8143c7ced4d18080d7a9a (git)
Affected: 0bbe30668d89ec8a309f28ced6d092c90fb23e8c , < 1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94 (git)
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Linux Linux Affected: 5.7
Unaffected: 0 , < 5.7 (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "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": [
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            "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": [
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              "version": "5.7"
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              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
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                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
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                  "versionEndExcluding": "7.2",
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              "negate": false,
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      "descriptions": [
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          "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."
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            "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"
          },
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              "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."
            }
          ]
        }
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          "url": "https://git.kernel.org/stable/c/ae128dd19040ee06a4f8143c7ced4d18080d7a9a"
        },
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          "url": "https://git.kernel.org/stable/c/1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74713",
    "datePublished": "2026-08-22T15:33:09.028Z",
    "dateReserved": "2026-08-15T05:44:03.928Z",
    "dateUpdated": "2026-08-25T05:41:56.127Z",
    "state": "PUBLISHED"
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      "date": "2026-09-15",
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      "percentile": "0.02088"
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      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "vhost_iotlb: bound map allocation in add_range",
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      "version": "2"
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    "redhat_vex": {
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      "current_release_date": "2026-08-25T08:55:31+00:00",
      "cve": "CVE-2026-74713",
      "id": "CVE-2026-74713",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "246",
      "product_status:known_not_affected": "28",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vhost_iotlb: bound map allocation in add_range",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74713.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:16:01Z",
      "cve": "CVE-2026-74713",
      "id": "CVE-2026-74713",
      "initial_release_date": "2026-08-26T01:11:56Z",
      "product_status:known_affected": "214",
      "product_status:known_not_affected": "143",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74713",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74713.json",
      "version": "4"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.


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.