CVE-2026-52959 (GCVE-0-2026-52959)

Vulnerability from cvelistv5 – Published: 2026-06-24 16:28 – Updated: 2026-06-28 06:37
VLAI
Title
virt: sev-guest: Do not use host-controlled page order in cleanup path
Summary
In 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.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 3e385c0d6ce88ac9916dcf84267bd5855d830748 , < 3f6fb0211b39aaa1b841260681dd02ca6b693ed5 (git)
Affected: 3e385c0d6ce88ac9916dcf84267bd5855d830748 , < 9e48b4f813d2c3db75d522aa82ab705ce04b7e2d (git)
Affected: 3e385c0d6ce88ac9916dcf84267bd5855d830748 , < 23e6a1ca04ae44806439a5a446e62e4d42e80bb4 (git)
Affected: 0b16521f95c875e79d657cb8d6911c15080dbb80 (git)
Affected: 6.13.8 , < 6.14 (semver)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.33 , ≤ 6.18.* (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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            "drivers/virt/coco/sev-guest/sev-guest.c"
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    "datePublished": "2026-06-24T16:28:40.391Z",
    "dateReserved": "2026-06-09T07:44:35.373Z",
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    "state": "PUBLISHED"
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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