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GHSA-WW8W-MGXM-5CF5

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

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

s390: Revert support for DCACHE_WORD_ACCESS

load_unaligned_zeropad() reads eight bytes from unaligned addresses and may cross page boundaries. It handles exceptions which may happen if reading from the second page results in an exception.

For pages which are donated to the Ultravisor for secure execution purposes the do_secure_storage_access() exception handler however does not handle such exceptions correctly. Such an exception may result in an endless exception loop which will never be resolved.

An attempt to fix this [1] turned out to be not sufficient. For now revert load_unaligned_zeropad() until this problem has been resolved in a proper way.

Note that the implementation of load_unaligned_zeropad() itself is correct. The revert is just a temporary workaround until there is complete fix for secure storage access exceptions.

[1] commit b00be77302d7 ("s390/mm: Add missing secure storage access fixups for donated memory")

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64369"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:19Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390: Revert support for DCACHE_WORD_ACCESS\n\nload_unaligned_zeropad() reads eight bytes from unaligned addresses and may\ncross page boundaries. It handles exceptions which may happen if reading\nfrom the second page results in an exception.\n\nFor pages which are donated to the Ultravisor for secure execution purposes\nthe do_secure_storage_access() exception handler however does not handle\nsuch exceptions correctly. Such an exception may result in an endless\nexception loop which will never be resolved.\n\nAn attempt to fix this [1] turned out to be not sufficient. For now revert\nload_unaligned_zeropad() until this problem has been resolved in a proper\nway.\n\nNote that the implementation of load_unaligned_zeropad() itself is\ncorrect. The revert is just a temporary workaround until there is complete\nfix for secure storage access exceptions.\n\n[1] commit b00be77302d7 (\"s390/mm: Add missing secure storage access fixups for donated memory\")",
  "id": "GHSA-ww8w-mgxm-5cf5",
  "modified": "2026-07-25T12:31:33Z",
  "published": "2026-07-25T12:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64369"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/37540b8c287fc817bdbd0c62bb75ad6eab0e5d03"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be79d285bea70d0edd5015bd487311bfa8cbebc9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c94806905e02cc8e17a69c822d93c41743b7ffc5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c9e0f1517631ac08987f8385817119bccf2f1f12"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64369 (GCVE-0-2026-64369)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-25 08:50

Title

s390: Revert support for DCACHE_WORD_ACCESS

Summary

In the Linux kernel, the following vulnerability has been resolved: s390: Revert support for DCACHE_WORD_ACCESS load_unaligned_zeropad() reads eight bytes from unaligned addresses and may cross page boundaries. It handles exceptions which may happen if reading from the second page results in an exception. For pages which are donated to the Ultravisor for secure execution purposes the do_secure_storage_access() exception handler however does not handle such exceptions correctly. Such an exception may result in an endless exception loop which will never be resolved. An attempt to fix this [1] turned out to be not sufficient. For now revert load_unaligned_zeropad() until this problem has been resolved in a proper way. Note that the implementation of load_unaligned_zeropad() itself is correct. The revert is just a temporary workaround until there is complete fix for secure storage access exceptions. [1] commit b00be77302d7 ("s390/mm: Add missing secure storage access fixups for donated memory")

Severity

No CVSS data available.

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/c9e0f1517631ac089…
https://git.kernel.org/stable/c/be79d285bea70d0ed…
https://git.kernel.org/stable/c/c94806905e02cc8e1…
https://git.kernel.org/stable/c/37540b8c287fc817b…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 802ba53eefc592a6a82231f74e19bafe3256f172 , < c9e0f1517631ac08987f8385817119bccf2f1f12 (git) Affected: 802ba53eefc592a6a82231f74e19bafe3256f172 , < be79d285bea70d0edd5015bd487311bfa8cbebc9 (git) Affected: 802ba53eefc592a6a82231f74e19bafe3256f172 , < c94806905e02cc8e17a69c822d93c41743b7ffc5 (git) Affected: 802ba53eefc592a6a82231f74e19bafe3256f172 , < 37540b8c287fc817bdbd0c62bb75ad6eab0e5d03 (git)
Linux	Linux	Affected: 6.7 Unaffected: 0 , < 6.7 (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/Kconfig",
            "arch/s390/include/asm/asm-extable.h",
            "arch/s390/include/asm/word-at-a-time.h",
            "arch/s390/mm/extable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "802ba53eefc592a6a82231f74e19bafe3256f172",
              "versionType": "git"
            },
            {
              "lessThan": "be79d285bea70d0edd5015bd487311bfa8cbebc9",
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              "version": "802ba53eefc592a6a82231f74e19bafe3256f172",
              "versionType": "git"
            },
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              "versionType": "git"
            },
            {
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              "version": "802ba53eefc592a6a82231f74e19bafe3256f172",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "arch/s390/include/asm/word-at-a-time.h",
            "arch/s390/mm/extable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
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                },
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390: Revert support for DCACHE_WORD_ACCESS\n\nload_unaligned_zeropad() reads eight bytes from unaligned addresses and may\ncross page boundaries. It handles exceptions which may happen if reading\nfrom the second page results in an exception.\n\nFor pages which are donated to the Ultravisor for secure execution purposes\nthe do_secure_storage_access() exception handler however does not handle\nsuch exceptions correctly. Such an exception may result in an endless\nexception loop which will never be resolved.\n\nAn attempt to fix this [1] turned out to be not sufficient. For now revert\nload_unaligned_zeropad() until this problem has been resolved in a proper\nway.\n\nNote that the implementation of load_unaligned_zeropad() itself is\ncorrect. The revert is just a temporary workaround until there is complete\nfix for secure storage access exceptions.\n\n[1] commit b00be77302d7 (\"s390/mm: Add missing secure storage access fixups for donated memory\")"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-25T08:50:22.543Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/37540b8c287fc817bdbd0c62bb75ad6eab0e5d03"
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      ],
      "title": "s390: Revert support for DCACHE_WORD_ACCESS",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64369",
    "datePublished": "2026-07-25T08:50:22.543Z",
    "dateReserved": "2026-07-19T15:36:31.783Z",
    "dateUpdated": "2026-07-25T08:50:22.543Z",
    "state": "PUBLISHED"
  },
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}

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.

Action not permitted

GHSA-WW8W-MGXM-5CF5

CVE-2026-64369 (GCVE-0-2026-64369)

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Nomenclature