Vulnerability-Lookup

GHSA-337Q-M32V-P95J

Vulnerability from github – Published: 2026-09-09 18:32 – Updated: 2026-09-10 06:31

Details

In the Linux kernel, the following vulnerability has been resolved:

KVM: s390: vsie: zero stale crypto bits

When shadowing crypto access bits from a format0 apcb (crycb 0 or 1), the bits 64..255 are unchanged from whatever is in the vsie page in the crycb and thus in the apcb. This gives a nested guest potential access to a device no longer available. Zero out the remaining bits.

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80921"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-09T17:17:47Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: vsie: zero stale crypto bits\n\nWhen shadowing crypto access bits from a format0 apcb (crycb 0 or 1),\nthe bits 64..255 are unchanged from whatever is in the vsie page in the\ncrycb and thus in the apcb. This gives a nested guest potential access\nto a device no longer available. Zero out the remaining bits.",
  "id": "GHSA-337q-m32v-p95j",
  "modified": "2026-09-10T06:31:41Z",
  "published": "2026-09-09T18:32:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80921"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80921 (GCVE-0-2026-80921)

Vulnerability from cvelistv5 – Published: 2026-09-09 16:19 – Updated: 2026-09-10 05:50

Title

KVM: s390: vsie: zero stale crypto bits

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: vsie: zero stale crypto bits When shadowing crypto access bits from a format0 apcb (crycb 0 or 1), the bits 64..255 are unchanged from whatever is in the vsie page in the crycb and thus in the apcb. This gives a nested guest potential access to a device no longer available. Zero out the remaining bits.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Assigner

Linux mitre root

References

9 references

URL	Tags
https://git.kernel.org/stable/c/d110b3297f11ef227…
https://git.kernel.org/stable/c/59d51550b5cb916bd…
https://git.kernel.org/stable/c/f6079dca67eccb5ea…
https://git.kernel.org/stable/c/087c19cc60a8caa1a…
https://git.kernel.org/stable/c/7d23489f51109e3eb…
https://git.kernel.org/stable/c/935eeba276012916c…
https://git.kernel.org/stable/c/d4bcd2df6d0d2af91…
https://git.kernel.org/stable/c/29b4f7bc2991313bd…
https://git.kernel.org/stable/c/34d5b5b646c91cfb9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < d110b3297f11ef227098b8a82ade2d5f123b7d2f (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < 59d51550b5cb916bda037673a721a404b3b47a0d (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < f6079dca67eccb5eabef9f72437948c66dc5131f (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < 087c19cc60a8caa1a08e1e434c8be2caf6c27733 (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < 7d23489f51109e3ebba5b5db8c5f0185af7b7fdf (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < 935eeba276012916c76243e5cbb843efd8fdb75d (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < d4bcd2df6d0d2af916b4fe1a533958778ea7c45b (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < 29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6 (git) Affected: 6b79de4b056e5a2febc0c61233d8f0ad7868e49c , < 34d5b5b646c91cfb9338d7a12c955a70ffb8c66b (git)
Linux	Linux	Affected: 4.20 Unaffected: 0 , < 4.20 (semver) Unaffected: 5.10.269 , ≤ 5.10.* (semver) Unaffected: 5.15.220 , ≤ 5.15.* (semver) Unaffected: 6.1.187 , ≤ 6.1.* (semver) Unaffected: 6.6.156 , ≤ 6.6.* (semver) Unaffected: 6.12.108 , ≤ 6.12.* (semver) Unaffected: 6.18.49 , ≤ 6.18.* (semver) Unaffected: 7.1.13 , ≤ 7.1.* (semver) Unaffected: 7.2.3 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kvm/vsie.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d110b3297f11ef227098b8a82ade2d5f123b7d2f",
              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
              "versionType": "git"
            },
            {
              "lessThan": "59d51550b5cb916bda037673a721a404b3b47a0d",
              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
              "versionType": "git"
            },
            {
              "lessThan": "f6079dca67eccb5eabef9f72437948c66dc5131f",
              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
              "versionType": "git"
            },
            {
              "lessThan": "087c19cc60a8caa1a08e1e434c8be2caf6c27733",
              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
              "versionType": "git"
            },
            {
              "lessThan": "7d23489f51109e3ebba5b5db8c5f0185af7b7fdf",
              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
              "versionType": "git"
            },
            {
              "lessThan": "935eeba276012916c76243e5cbb843efd8fdb75d",
              "status": "affected",
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              "versionType": "git"
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              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
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              "status": "affected",
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              "versionType": "git"
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              "status": "affected",
              "version": "6b79de4b056e5a2febc0c61233d8f0ad7868e49c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
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            "arch/s390/kvm/vsie.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "lessThan": "4.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.269",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.220",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.187",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.156",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.108",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.49",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.269",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.220",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.187",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.156",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.108",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.49",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.13",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.3",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: vsie: zero stale crypto bits\n\nWhen shadowing crypto access bits from a format0 apcb (crycb 0 or 1),\nthe bits 64..255 are unchanged from whatever is in the vsie page in the\ncrycb and thus in the apcb. This gives a nested guest potential access\nto a device no longer available. Zero out the remaining bits."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached when an s390 KVM guest executes the privileged SIE instruction (B2/14), intercepted through handle_instruction() to kvm_s390_handle_vsie() and setup_apcb10(); that is a local guest/KVM ioctl path with no network, Bluetooth, or USB exposure.\nAC:L - An L1 guest that first runs a FORMAT-2 nested SCB (setup_apcb11 fills all 256 APCB bits) and then a FORMAT-0/1 SCB on a recycled vsie page hits setup_apcb10() deterministically; get_vsie_page() reuses pages without clearing crycb, so leftover bits 64-255 persist with no race or uncontrolled memory layout.\nPR:L - SIE requires guest supervisor state, i.e. the tenant guest kernel or an unprivileged host kvm-group user running QEMU, not host root; kvm_s390_handle_vsie() has no host capability gate, and user namespaces cannot substitute for this path, so privileges stay Low rather than High.\nUI:N - The attacker guest issues SIE and uses the over-permissive shadow APCB itself; vsie page reuse and crycb shadowing run automatically inside KVM with no victim mount, click, or other user action.\nS:C - Leftover APCB bits grant a nested guest millicode-enforced access to host AP adapters/domains outside its delegated matrix, crossing the KVM nested-virt and vfio-ap passthrough boundary into another guest\u0027s or the host zcrypt authority, equivalent to an IOMMU/device isolation bypass.\nC:H - Unauthorized APQNs let the nested guest issue NQAP/DQAP against queues that may now belong to the host zcrypt stack or another tenant, disclosing cryptographic request/response data and key material on those adapters/domains.\nI:H - The nested guest can enqueue arbitrary AP requests and change hardware queue state on adapters and domains 64-255 that the current shadow should have cleared, corrupting crypto operations the host believes are exclusive to another consumer.\nA:H - With those leftover APQNs the nested guest can PQAP(ZAPQ)-reset or flood shared queues, denying host or sibling-guest crypto services (pkey, secure-key LUKS, openCryptoki) that depend on the same physical adapter/domain."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-10T05:50:22.520Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f"
        },
        {
          "url": "https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d"
        },
        {
          "url": "https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f"
        },
        {
          "url": "https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733"
        },
        {
          "url": "https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf"
        },
        {
          "url": "https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d"
        },
        {
          "url": "https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b"
        },
        {
          "url": "https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6"
        },
        {
          "url": "https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b"
        }
      ],
      "title": "KVM: s390: vsie: zero stale crypto bits",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80921",
    "datePublished": "2026-09-09T16:19:42.335Z",
    "dateReserved": "2026-08-26T14:34:25.801Z",
    "dateUpdated": "2026-09-10T05:50:22.520Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-337Q-M32V-P95J

CVE-2026-80921 (GCVE-0-2026-80921)

Tags

Sightings

Nomenclature