CVE-2026-63938 (GCVE-0-2026-63938)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-07-20 13:41
VLAI
Title
KVM: SEV: Check PSC request indices against the actual size of the buffer
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Check PSC request indices against the actual size of the buffer When processing Page State Change (PSC) requests, validate the PSC buffer against the effective size of the scratch area, which could be less than the maximum size if the guest provided a pointer that isn't exactly at the start of the GHCB shared buffer.
Severity
9.3 (Critical)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 5198f70c09a5f6e9e5f5a0a2c6b388f24294b176 (git)
Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 75c8d1d7291268b479794fba5808971dc2f5eaf3 (git)
Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 505a3b94535583e4265360e2621734e355ef263d (git)
Affected: 9b54e248d2644be71cb394eb85f31ad99e023a05 , < 121d88de56bc5c0ba0ce2f6381af67f948a7e7c1 (git)
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Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.93 , ≤ 6.12.* (semver)
Unaffected: 6.18.35 , ≤ 6.18.* (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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        }
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    "datePublished": "2026-07-19T14:55:35.168Z",
    "dateReserved": "2026-07-19T07:54:57.022Z",
    "dateUpdated": "2026-07-20T13:41:40.069Z",
    "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

Author Source Type Date Other

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.


Detection rules are retrieved from Rulezet.