GHSA-H9M6-P5F9-C339
Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 12:31In the Linux kernel, the following vulnerability has been resolved:
vhost/vdpa: reject VRING_NUM larger than device max
vhost_vring_set_num() accepts any non-zero power-of-two queue size that fits in 16 bits. vhost-vdpa then passes that value to set_vq_num() without comparing it with get_vq_num_max().
A process with access to /dev/vhost-vdpa-* can therefore configure a queue larger than the device advertises. With vdpa_sim, the worker can walk descriptors beyond the mapped descriptor ring. KASAN reports a 16-byte out-of-bounds read, corresponding to one vring_desc, in the vringh IOTLB path:
BUG: KASAN: out-of-bounds in _copy_from_iter Read of size 16 copy_from_iotlb copydesc_iotlb vringh_getdesc_iotlb vdpasim_net_work
Cache get_vq_num_max() immediately after reset. Some backends derive it from writable queue-size state, so querying it after SET_NUM may return the current size instead of the device capability. Invalidate the cached value before reset so a failed reset leaves SET_NUM disabled.
For VHOST_SET_VRING_NUM, copy the complete vring state once and use the same index and size for validation, vq->num, and set_vq_num(). This ensures that validation and use operate on the same copied values.
{
"affected": [],
"aliases": [
"CVE-2026-97994"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-25T11:17:27Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost/vdpa: reject VRING_NUM larger than device max\n\nvhost_vring_set_num() accepts any non-zero power-of-two queue size that\nfits in 16 bits. vhost-vdpa then passes that value to set_vq_num()\nwithout comparing it with get_vq_num_max().\n\nA process with access to /dev/vhost-vdpa-* can therefore configure a\nqueue larger than the device advertises. With vdpa_sim, the worker can\nwalk descriptors beyond the mapped descriptor ring. KASAN reports a\n16-byte out-of-bounds read, corresponding to one vring_desc, in the\nvringh IOTLB path:\n\n BUG: KASAN: out-of-bounds in _copy_from_iter\n Read of size 16\n copy_from_iotlb\n copydesc_iotlb\n vringh_getdesc_iotlb\n vdpasim_net_work\n\nCache get_vq_num_max() immediately after reset. Some backends derive\nit from writable queue-size state, so querying it after SET_NUM may\nreturn the current size instead of the device capability. Invalidate\nthe cached value before reset so a failed reset leaves SET_NUM\ndisabled.\n\nFor VHOST_SET_VRING_NUM, copy the complete vring state once and use\nthe same index and size for validation, vq-\u003enum, and set_vq_num().\nThis ensures that validation and use operate on the same copied values.",
"id": "GHSA-h9m6-p5f9-c339",
"modified": "2026-09-25T12:31:32Z",
"published": "2026-09-25T12:31:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97994"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1d09201d81b7d3e276860cc7b7dbf6c6cbe8e9b4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/59522639a7d71cff4e20d594d0b9ea30dd0c77e0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/68232102f20fc961327fb9e0f605a7eaadf030a9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ccb1dc7c527f8c925925cf92afc76ae590dac311"
}
],
"schema_version": "1.4.0",
"severity": []
}
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