xen/gntalloc: validate grant count before allocation
In the Linux kernel, the following vulnerability has been resolved: xen/gntalloc: validate grant count before allocation gntalloc_ioctl_alloc() allocates the grant-id array before checking whether the requested count fits within the global grant limit. Counts above that limit cannot succeed, so reject them before the user-controlled allocation reaches kcalloc(). Use a subtraction-based check while holding gref_mutex so adding the requested count cannot wrap. Also cast the count before advancing the per-file index so the page-size multiplication is performed in 64-bit arithmetic.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.271, 5.15.222, 6.1.189, 6.12.111, 6.18.53, 6.6.158
- CVEs
- CVE-2026-98900
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 16:16 UTC · Revision 1
Source evidence
xen/gntalloc: validate grant count before allocation
core-osv · Original sourcePublished 23 Oct 2026, 11:54 UTC
In the Linux kernel, the following vulnerability has been resolved: xen/gntalloc: validate grant count before allocation gntalloc_ioctl_alloc() allocates the grant-id array before checking whether the requested count fits within the global grant limit. Counts above that limit cannot succeed, so reject them before the user-controlled allocation reaches kcalloc(). Use a subtraction-based check while holding gref_mutex so adding the requested count cannot wrap. Also cast the count before advancing the per-file index so the page-size multiplication is performed in 64-bit arithmetic.
osv:CVE-2026-98900
Kernel
Fixed versions: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53
Complete source record
{
"id": "815b30b94e9dbfc2b6b17d1153f6484bfe01235cca6806d0f7275ae408fe2ac6",
"url": "https://osv.dev/vulnerability/CVE-2026-98900",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "xen/gntalloc: validate grant count before allocation",
"summary": "In the Linux kernel, the following vulnerability has been resolved: xen/gntalloc: validate grant count before allocation gntalloc_ioctl_alloc() allocates the grant-id array before checking whether the requested count fits within the global grant limit. Counts above that limit cannot succeed, so reject them before the user-controlled allocation reaches kcalloc(). Use a subtraction-based check while holding gref_mutex so adding the requested count cannot wrap. Also cast the count before advancing the per-file index so the page-size multiplication is performed in 64-bit arithmetic.",
"evidence": "osv:CVE-2026-98900",
"products": [
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"name": {
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"evidence": "/affected/1/package/name"
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"prerequisites": [],
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{
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"severity": "unknown",
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"aliases": [
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"package": {
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"database_specific": {
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],
"modified": "2026-10-28T02:30:30.120592901Z",
"provider": "osv",
"references": [
"https://git.kernel.org/stable/c/2299822f3f466b5dcad2377bf63986199f881a6b",
"https://git.kernel.org/stable/c/231542f4e43cf9837cb520664545e85fbe666b7b",
"https://git.kernel.org/stable/c/641de086a05f349de7fc548612432bc2fed721ca",
"https://git.kernel.org/stable/c/71a0cf87e19fb35c4292ca88985e376e613c900a",
"https://git.kernel.org/stable/c/720554c04acba80018ded069d3e0984bebaee891",
"https://git.kernel.org/stable/c/84d5727cef8eb9c8a28210ad248f1c70b223b065",
"https://git.kernel.org/stable/c/e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98900.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-98900",
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
],
"provider_metadata": {
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"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98900.json"
}
},
"related_cves": [
{
"value": "CVE-2026-98900",
"evidence": "/id"
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],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 497230,
"published_at": "2026-10-23T11:54:10.566+00:00"
}