{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74713", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.928Z", "datePublished": "2026-08-22T15:33:09.028Z", "dateUpdated": "2026-10-16T19:16:11.209Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-15T10:09:21.582Z" }, "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": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "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" ], "versions": [ { "version": "0bbe30668d89ec8a309f28ced6d092c90fb23e8c", "lessThan": "b57164cdddb46924ff9fa191b727ca097744de88", "status": "affected", "versionType": "git" }, { "version": "0bbe30668d89ec8a309f28ced6d092c90fb23e8c", "lessThan": "ae128dd19040ee06a4f8143c7ced4d18080d7a9a", "status": "affected", "versionType": "git" }, { "version": "0bbe30668d89ec8a309f28ced6d092c90fb23e8c", "lessThan": "1ed35ac7f3fe2b4396bdd29ac3a7f0ebc0829e94", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "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" ], "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.2" } ] } ] } ], "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" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74713", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:15:21.643384Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:16:11.209Z" } } ] } }