CVE-2026-64289 (GCVE-0-2026-64289)
Vulnerability from cvelistv5
Published
2026-07-25 08:49
Modified
2026-08-17 04:52
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Set upper bounds on cache invalidation entry_num and entry_len
iommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,
each bounded only by U32_MAX. An entry_len beyond the kernel's struct size
makes the copy helper verify the extra bytes are zero, scanning that excess
in one uninterruptible pass; a multi-gigabyte value over zeroed user memory
trips the soft-lockup watchdog.
A large entry_num is the other half, driving the backend invalidation loop
with no reschedule. The VT-d nested handler, for one, copies each entry and
flushes caches per iteration, pinning the CPU on a non-preemptible kernel.
Cap both in the ioctl. entry_len is held under PAGE_SIZE, above any request
struct, and entry_num under 1 << 19, the order of a hardware invalidation
queue and well beyond any real batch, bounding the per-call loop length.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
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{
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"product": "Linux",
"programFiles": [
"drivers/iommu/iommufd/hw_pagetable.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"versionType": "git"
},
{
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"versions": [
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"version": "0",
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{
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"status": "unaffected",
"version": "6.12.96",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.1.4",
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{
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommufd: Set upper bounds on cache invalidation entry_num and entry_len\n\niommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,\neach bounded only by U32_MAX. An entry_len beyond the kernel\u0027s struct size\nmakes the copy helper verify the extra bytes are zero, scanning that excess\nin one uninterruptible pass; a multi-gigabyte value over zeroed user memory\ntrips the soft-lockup watchdog.\n\nA large entry_num is the other half, driving the backend invalidation loop\nwith no reschedule. The VT-d nested handler, for one, copies each entry and\nflushes caches per iteration, pinning the CPU on a non-preemptible kernel.\n\nCap both in the ioctl. entry_len is held under PAGE_SIZE, above any request\nstruct, and entry_num under 1 \u003c\u003c 19, the order of a hardware invalidation\nqueue and well beyond any real batch, bounding the per-call loop length."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:52:45.289Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/d2bd041e0efaf7d81789779b135279d18b33d6d5"
},
{
"url": "https://git.kernel.org/stable/c/32ca4aed2a66205b072fcfecabe220289a8149ff"
},
{
"url": "https://git.kernel.org/stable/c/2c6381d90898089287e0a358f06f89f6b4b389f2"
},
{
"url": "https://git.kernel.org/stable/c/4d70986002f2f3eaaed89124fb2522bded38b016"
}
],
"title": "iommufd: Set upper bounds on cache invalidation entry_num and entry_len",
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"cveMetadata": {
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"cveId": "CVE-2026-64289",
"datePublished": "2026-07-25T08:49:29.434Z",
"dateReserved": "2026-07-19T15:36:31.778Z",
"dateUpdated": "2026-08-17T04:52:45.289Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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