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vuln-cve/data/2026/80xxx/CVE-2026-80895.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-80895",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-08-26T14:34:25.800Z",
"datePublished": "2026-09-04T17:11:10.880Z",
"dateUpdated": "2026-09-04T17:11:10.880Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-09-04T17:11:10.880Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmshv: Order pt_vp_array publish against irqfd assertion path\n\nmshv_partition_ioctl_create_vp() initialises a VP struct (allocations,\nmutex_init, init_waitqueue_head, page mappings) and then publishes the\npointer into partition->pt_vp_array. Several ISR paths read this array\nlocklessly: the intercept ISR, the two scheduler ISRs, and\nmshv_try_assert_irq_fast() on the irqfd fast path.\n\nOf these, only mshv_try_assert_irq_fast() can structurally race the\npublish. It runs from an eventfd waker without holding pt_mutex, and\nMSHV_IRQFD does not require the target lapic_apic_id (== vp_index) to\nrefer to an existing VP at registration time. A user can therefore\nregister an irqfd targeting a yet-to-be-created VP, then trigger\nmshv_try_assert_irq_fast() concurrently with MSHV_CREATE_VP for the\nsame index. On weakly-ordered architectures the reader can observe a\nnon-NULL pointer in pt_vp_array before the initialising stores to the\nVP struct become visible, leading to use of partially-initialised\nfields (e.g. vp_register_page).\n\nThe other ISR readers cannot reach this race: the hypervisor will not\ngenerate intercept or scheduler messages for a VP that has never been\ntold to run, and the user can only call MSHV_RUN_VP on the VP fd\nreturned by MSHV_CREATE_VP, which by construction is returned after\nthe publish. Leave those readers as plain loads.\n\nUse smp_store_release() in mshv_partition_ioctl_create_vp() to publish\nthe pointer, and pair it with smp_load_acquire() in\nmshv_try_assert_irq_fast(). On x86 these compile to plain accesses\nunder TSO; on ARM64 they emit one-instruction acquire/release barriers,\nacceptable on this fast path.\n\nThe destroy-side path (destroy_partition() clearing pt_vp_array[i] to\nNULL after kfree(vp)) has a separate ordering and lifetime concern\nthat is out of scope here."
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/hv/mshv_eventfd.c",
"drivers/hv/mshv_root_main.c"
],
"versions": [
{
"version": "621191d709b14882270dfd8ea5d7d6cdfebe2c35",
"lessThan": "062aa5dcc49a9ad96726a80c2a0ab0a1233bc2b9",
"status": "affected",
"versionType": "git"
},
{
"version": "621191d709b14882270dfd8ea5d7d6cdfebe2c35",
"lessThan": "eba2bf5daa7933f94c53ebbbf0f567d4274716df",
"status": "affected",
"versionType": "git"
},
{
"version": "621191d709b14882270dfd8ea5d7d6cdfebe2c35",
"lessThan": "b098dc869219c15dc49bf9cf63fb5fc1481d3373",
"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/hv/mshv_eventfd.c",
"drivers/hv/mshv_root_main.c"
],
"versions": [
{
"version": "6.15",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.15",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.44",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.1.8",
"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": "6.15",
"versionEndExcluding": "6.18.44"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.15",
"versionEndExcluding": "7.1.8"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.15",
"versionEndExcluding": "7.2"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/062aa5dcc49a9ad96726a80c2a0ab0a1233bc2b9"
},
{
"url": "https://git.kernel.org/stable/c/eba2bf5daa7933f94c53ebbbf0f567d4274716df"
},
{
"url": "https://git.kernel.org/stable/c/b098dc869219c15dc49bf9cf63fb5fc1481d3373"
}
],
"title": "mshv: Order pt_vp_array publish against irqfd assertion path",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
}
}