Vulnerability-Lookup

EUVD-2026-364661

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 08:33

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

JSON

To clipboard

{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T08:33:30.713409+00:00",
  "id": "EUVD-2026-364661"
}

CVE-2026-23100 (GCVE-0-2026-23100)

Vulnerability from cvelistv5 – Published: 2026-02-04 16:08 – Updated: 2026-09-08 08:44

Title

mm/hugetlb: fix hugetlb_pmd_shared()

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix hugetlb_pmd_shared() Patch series "mm/hugetlb: fixes for PMD table sharing (incl. using mmu_gather)", v3. One functional fix, one performance regression fix, and two related comment fixes. I cleaned up my prototype I recently shared [1] for the performance fix, deferring most of the cleanups I had in the prototype to a later point. While doing that I identified the other things. The goal of this patch set is to be backported to stable trees "fairly" easily. At least patch #1 and #4. Patch #1 fixes hugetlb_pmd_shared() not detecting any sharing Patch #2 + #3 are simple comment fixes that patch #4 interacts with. Patch #4 is a fix for the reported performance regression due to excessive IPI broadcasts during fork()+exit(). The last patch is all about TLB flushes, IPIs and mmu_gather. Read: complicated There are plenty of cleanups in the future to be had + one reasonable optimization on x86. But that's all out of scope for this series. Runtime tested, with a focus on fixing the performance regression using the original reproducer [2] on x86. This patch (of 4): We switched from (wrongly) using the page count to an independent shared count. Now, shared page tables have a refcount of 1 (excluding speculative references) and instead use ptdesc->pt_share_count to identify sharing. We didn't convert hugetlb_pmd_shared(), so right now, we would never detect a shared PMD table as such, because sharing/unsharing no longer touches the refcount of a PMD table. Page migration, like mbind() or migrate_pages() would allow for migrating folios mapped into such shared PMD tables, even though the folios are not exclusive. In smaps we would account them as "private" although they are "shared", and we would be wrongly setting the PM_MMAP_EXCLUSIVE in the pagemap interface. Fix it by properly using ptdesc_pmd_is_shared() in hugetlb_pmd_shared().

Severity

No CVSS data available.

Assigner

Linux mitre root Scorecard

References

9 references

URL	Tags
https://git.kernel.org/stable/c/8ae48255bcb17b324…
https://git.kernel.org/stable/c/bf3c2affe245cf831…
https://git.kernel.org/stable/c/5b2aec77f92265a90…
https://git.kernel.org/stable/c/51dcf459845fd28f5…
https://git.kernel.org/stable/c/3a18b452dd5f7f165…
https://git.kernel.org/stable/c/69c4e241ff13545d4…
https://git.kernel.org/stable/c/ca1a47cd3f5f4c46c…
https://cert-portal.siemens.com/productcert/html/…
https://cert-portal.siemens.com/productcert/html/…

Impacted products

8 products

Vendor	Product	Version
Linux	Linux	Affected: 94b4b41d0cdf5cfd4d4325bc0e6e9e0d0e996133 , < 8ae48255bcb17b32436be97553dca848730d365f (git) Affected: 8410996eb6fea116fe1483ed977aacf580eee7b4 , < bf3c2affe245cf831866ddc8f736ae6a22cdc11c (git) Affected: 02333ac1c35370517a19a4a131332a9690c6a5c7 , < 5b2aec77f92265a9028c5f632bdd9af5b57ec3a3 (git) Affected: 56b274473d6e7e7375f2d0a2b4aca11d67c6b52f , < 51dcf459845fd28f5a0d83d408a379b274ec5cc5 (git) Affected: 2e31443a0d18ae43b9d29e02bf0563f07772193d , < 3a18b452dd5f7f1652c2e92f8ae769aa17a66c9e (git) Affected: 59d9094df3d79443937add8700b2ef1a866b1081 , < 69c4e241ff13545d410a8b2a688c932182a858bf (git) Affected: 59d9094df3d79443937add8700b2ef1a866b1081 , < ca1a47cd3f5f4c46ca188b1c9a27af87d1ab2216 (git) Affected: 5.10.239 , < 5.10.253 (semver) Affected: 5.15.186 , < 5.15.203 (semver) Affected: 6.1.142 , < 6.1.167 (semver) Affected: 6.6.72 , < 6.6.127 (semver) Affected: 6.12.9 , < 6.12.74 (semver)
Linux	Linux	Affected: 6.13 Unaffected: 0 , < 6.13 (semver) Unaffected: 5.10.253 , ≤ 5.10.* (semver) Unaffected: 5.15.203 , ≤ 5.15.* (semver) Unaffected: 6.1.167 , ≤ 6.1.* (semver) Unaffected: 6.6.127 , ≤ 6.6.* (semver) Unaffected: 6.12.74 , ≤ 6.12.* (semver) Unaffected: 6.18.8 , ≤ 6.18.* (semver) Unaffected: 6.19 , ≤ * (original_commit_for_fix)
Siemens	SIMATIC S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.6 , < * (custom)
Siemens	SIMATIC S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.5 , < * (custom)
Siemens	SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP	Affected: V3.1.6 , < * (custom)
Siemens	SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP	Affected: V3.1.5 , < * (custom)
Siemens	SIPLUS S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.6 , < * (custom)
Siemens	SIPLUS S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.5 , < * (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "affected": [
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.5",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.5",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.5",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.5",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.5",
                "versionType": "custom"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-08T08:44:53.951Z",
          "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
          "shortName": "siemens-SADP"
        },
        "references": [
          {
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
          },
          {
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
          }
        ],
        "x_adpType": "supplier"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/hugetlb.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8ae48255bcb17b32436be97553dca848730d365f",
              "status": "affected",
              "version": "94b4b41d0cdf5cfd4d4325bc0e6e9e0d0e996133",
              "versionType": "git"
            },
            {
              "lessThan": "bf3c2affe245cf831866ddc8f736ae6a22cdc11c",
              "status": "affected",
              "version": "8410996eb6fea116fe1483ed977aacf580eee7b4",
              "versionType": "git"
            },
            {
              "lessThan": "5b2aec77f92265a9028c5f632bdd9af5b57ec3a3",
              "status": "affected",
              "version": "02333ac1c35370517a19a4a131332a9690c6a5c7",
              "versionType": "git"
            },
            {
              "lessThan": "51dcf459845fd28f5a0d83d408a379b274ec5cc5",
              "status": "affected",
              "version": "56b274473d6e7e7375f2d0a2b4aca11d67c6b52f",
              "versionType": "git"
            },
            {
              "lessThan": "3a18b452dd5f7f1652c2e92f8ae769aa17a66c9e",
              "status": "affected",
              "version": "2e31443a0d18ae43b9d29e02bf0563f07772193d",
              "versionType": "git"
            },
            {
              "lessThan": "69c4e241ff13545d410a8b2a688c932182a858bf",
              "status": "affected",
              "version": "59d9094df3d79443937add8700b2ef1a866b1081",
              "versionType": "git"
            },
            {
              "lessThan": "ca1a47cd3f5f4c46ca188b1c9a27af87d1ab2216",
              "status": "affected",
              "version": "59d9094df3d79443937add8700b2ef1a866b1081",
              "versionType": "git"
            },
            {
              "lessThan": "5.10.253",
              "status": "affected",
              "version": "5.10.239",
              "versionType": "semver"
            },
            {
              "lessThan": "5.15.203",
              "status": "affected",
              "version": "5.15.186",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.167",
              "status": "affected",
              "version": "6.1.142",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.127",
              "status": "affected",
              "version": "6.6.72",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.74",
              "status": "affected",
              "version": "6.12.9",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/hugetlb.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.13"
            },
            {
              "lessThan": "6.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.127",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.74",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "5.10.239",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.203",
                  "versionStartIncluding": "5.15.186",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.167",
                  "versionStartIncluding": "6.1.142",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.127",
                  "versionStartIncluding": "6.6.72",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.74",
                  "versionStartIncluding": "6.12.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.8",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix hugetlb_pmd_shared()\n\nPatch series \"mm/hugetlb: fixes for PMD table sharing (incl.  using\nmmu_gather)\", v3.\n\nOne functional fix, one performance regression fix, and two related\ncomment fixes.\n\nI cleaned up my prototype I recently shared [1] for the performance fix,\ndeferring most of the cleanups I had in the prototype to a later point. \nWhile doing that I identified the other things.\n\nThe goal of this patch set is to be backported to stable trees \"fairly\"\neasily. At least patch #1 and #4.\n\nPatch #1 fixes hugetlb_pmd_shared() not detecting any sharing\nPatch #2 + #3 are simple comment fixes that patch #4 interacts with.\nPatch #4 is a fix for the reported performance regression due to excessive\nIPI broadcasts during fork()+exit().\n\nThe last patch is all about TLB flushes, IPIs and mmu_gather.\nRead: complicated\n\nThere are plenty of cleanups in the future to be had + one reasonable\noptimization on x86. But that\u0027s all out of scope for this series.\n\nRuntime tested, with a focus on fixing the performance regression using\nthe original reproducer [2] on x86.\n\n\nThis patch (of 4):\n\nWe switched from (wrongly) using the page count to an independent shared\ncount.  Now, shared page tables have a refcount of 1 (excluding\nspeculative references) and instead use ptdesc-\u003ept_share_count to identify\nsharing.\n\nWe didn\u0027t convert hugetlb_pmd_shared(), so right now, we would never\ndetect a shared PMD table as such, because sharing/unsharing no longer\ntouches the refcount of a PMD table.\n\nPage migration, like mbind() or migrate_pages() would allow for migrating\nfolios mapped into such shared PMD tables, even though the folios are not\nexclusive.  In smaps we would account them as \"private\" although they are\n\"shared\", and we would be wrongly setting the PM_MMAP_EXCLUSIVE in the\npagemap interface.\n\nFix it by properly using ptdesc_pmd_is_shared() in hugetlb_pmd_shared()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-23T16:03:51.647Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8ae48255bcb17b32436be97553dca848730d365f"
        },
        {
          "url": "https://git.kernel.org/stable/c/bf3c2affe245cf831866ddc8f736ae6a22cdc11c"
        },
        {
          "url": "https://git.kernel.org/stable/c/5b2aec77f92265a9028c5f632bdd9af5b57ec3a3"
        },
        {
          "url": "https://git.kernel.org/stable/c/51dcf459845fd28f5a0d83d408a379b274ec5cc5"
        },
        {
          "url": "https://git.kernel.org/stable/c/3a18b452dd5f7f1652c2e92f8ae769aa17a66c9e"
        },
        {
          "url": "https://git.kernel.org/stable/c/69c4e241ff13545d410a8b2a688c932182a858bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/ca1a47cd3f5f4c46ca188b1c9a27af87d1ab2216"
        }
      ],
      "title": "mm/hugetlb: fix hugetlb_pmd_shared()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23100",
    "datePublished": "2026-02-04T16:08:22.592Z",
    "dateReserved": "2026-01-13T15:37:45.965Z",
    "dateUpdated": "2026-09-08T08:44:53.951Z",
    "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.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

EUVD-2026-364661

CVE-2026-23100 (GCVE-0-2026-23100)

Tags

Sightings

Nomenclature

Related by attack behaviour