GHSA-RJ55-92M8-99MG
Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-28 09:31In the Linux kernel, the following vulnerability has been resolved:
virt: sev-guest: Do not use host-controlled page order in cleanup path
When issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST), get_ext_report() allocates a buffer to retrieve a certificate blob from the host, keeping track of its size in report_req->certs_len.
However, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating an invalid buffer size, as well as the expected length of such buffer. get_ext_report() subsequently updates report_req->certs_len with the host-controlled value, and cleans up the buffer by computing a page order from such value. This is incorrect, as the host-provided length may not match the page order of the original allocation, potentially resulting in corruption in the page allocator.
Fix this by using alloc_pages_exact() instead, and reusing @npages to compute the size passed to free_pages_exact(). For consistency, also use @npages to compute the size when allocating the pages, even though this last change has no functional effect.
{
"affected": [],
"aliases": [
"CVE-2026-52959"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-24T17:17:06Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirt: sev-guest: Do not use host-controlled page order in cleanup path\n\nWhen issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST),\nget_ext_report() allocates a buffer to retrieve a certificate blob from the\nhost, keeping track of its size in report_req-\u003ecerts_len.\n\nHowever, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating\nan invalid buffer size, as well as the expected length of such buffer.\nget_ext_report() subsequently updates report_req-\u003ecerts_len with the\nhost-controlled value, and cleans up the buffer by computing a page order\nfrom such value. This is incorrect, as the host-provided length may not\nmatch the page order of the original allocation, potentially resulting\nin corruption in the page allocator.\n\nFix this by using alloc_pages_exact() instead, and reusing @npages to\ncompute the size passed to free_pages_exact(). For consistency, also\nuse @npages to compute the size when allocating the pages, even though\nthis last change has no functional effect.",
"id": "GHSA-rj55-92m8-99mg",
"modified": "2026-06-28T09:31:37Z",
"published": "2026-06-24T18:32:41Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52959"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/23e6a1ca04ae44806439a5a446e62e4d42e80bb4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3f6fb0211b39aaa1b841260681dd02ca6b693ed5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9e48b4f813d2c3db75d522aa82ab705ce04b7e2d"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.