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vuln-cve/data/2026/64xxx/CVE-2026-64293.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-64293",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-07-19T15:36:31.778Z",
"datePublished": "2026-07-25T08:49:31.945Z",
"dateUpdated": "2026-10-19T20:38:22.244Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-17T04:52:50.497Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommufd: Use sizeof(*hdr) instead of sizeof(hdr) in veventq read\n\nThe bound-check in iommufd_veventq_fops_read() for the normal vEVENT\npath uses sizeof(hdr) where the surrounding code uses sizeof(*hdr):\n\n\tif (!vevent_for_lost_events_header(cur) &&\n\t sizeof(hdr) + cur->data_len > count - done) {\n\nhdr is declared as struct iommufd_vevent_header *, so sizeof(hdr)\nevaluates to the size of the pointer. Surrounding code uses\nsizeof(*hdr) consistently:\n\n\tif (done >= count || sizeof(*hdr) > count - done) {\n\t...\n\tif (copy_to_user(buf + done, hdr, sizeof(*hdr))) {\n\t...\n\tdone += sizeof(*hdr);\n\nstruct iommufd_vevent_header is currently 8 bytes (two __u32 fields,\nflags and sequence), so on 64-bit (sizeof(void *) == 8) the two\nexpressions happen to be equal and the check works as intended.\n\nOn 32-bit (sizeof(void *) == 4) the check under-counts the header by\n4 bytes: a vEVENT whose data_len causes 8 + cur->data_len to exceed\ncount - done while 4 + cur->data_len does not will pass the check,\nthen the loop will copy_to_user 8 bytes of header followed by data_len\nbytes of payload, writing past the user-supplied buffer.\n\nIt is also a latent bug for any future expansion of struct\niommufd_vevent_header beyond sizeof(void *) on 64-bit; the check\nshould not depend on the type happening to match the host pointer\nwidth.\n\nUse sizeof(*hdr) to match the rest of the function and the actual\namount that will be copied."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The vulnerable function is reached through read() on a locally held iommufd vEVENTQ file descriptor; it is not directly network- or device-packet-facing.\nAC:L - On an affected 32-bit deployment, the attacker can deterministically queue an event and choose a count that is one to four bytes too small; no race or uncontrollable condition is required.\nPR:L - No capability check occurs during the vulnerable read, and an unprivileged VMM or user granted an iommufd/vEVENTQ descriptor can invoke it without real init-namespace root.\nUI:N - Exploitation requires only attacker-controlled event generation and a read syscall; no separate victim action is required.\nS:U - The corruption occurs through the host kernel's userspace API and does not itself bypass an IOMMU boundary or demonstrate a guest-to-host escape.\nC:H - The four-byte overwrite can replace a complete pointer or control word in a 32-bit event consumer, potentially enabling code execution and disclosure of arbitrary process secrets.\nI:H - The kernel writes up to four payload bytes beyond the declared userspace buffer, which can corrupt a full 32-bit control value and potentially permit control-flow hijacking.\nA:H - The overwrite can crash a privileged VMM or other event-consuming service, and controllable event generation permits the condition to be triggered repeatedly."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/iommu/iommufd/eventq.c"
],
"versions": [
{
"version": "e36ba5ab808ef6237c3148d469c8238674230e2b",
"lessThan": "04a177f91160ee18da98f5689482cf0f589ec869",
"status": "affected",
"versionType": "git"
},
{
"version": "e36ba5ab808ef6237c3148d469c8238674230e2b",
"lessThan": "0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72",
"status": "affected",
"versionType": "git"
},
{
"version": "e36ba5ab808ef6237c3148d469c8238674230e2b",
"lessThan": "be93d186ae88a92e7aa77e122d4e661fa57b1e39",
"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/iommu/iommufd/eventq.c"
],
"versions": [
{
"version": "6.15",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.15",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.39",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.1.4",
"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": "6.18.39"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.15",
"versionEndExcluding": "7.1.4"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.15",
"versionEndExcluding": "7.2"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/04a177f91160ee18da98f5689482cf0f589ec869"
},
{
"url": "https://git.kernel.org/stable/c/0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72"
},
{
"url": "https://git.kernel.org/stable/c/be93d186ae88a92e7aa77e122d4e661fa57b1e39"
}
],
"title": "iommufd: Use sizeof(*hdr) instead of sizeof(hdr) in veventq read",
"x_generator": {
"engine": "bippy-1.2.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"id": "CVE-2026-64293",
"role": "CISA Coordinator",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-10-16T15:38:30.670764Z"
}
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"type": "CWE",
"cweId": "CWE-787",
"description": "CWE-787 Out-of-bounds Write"
}
]
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-10-19T20:38:22.244Z"
}
}
]
}
}