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CVE-2026-23100
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().
Dieser Datensatz: Live-Anbindung— zuletzt abgerufen: 24. September 2026 um 05:07.
Direkt aus NVD, CISA oder vom Hersteller übernommen — teils auf Englisch, unverändert gegenüber der Quelle.
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().
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector
LOCAL
Privileges Required
LOW
User Interaction
NONE
Vertraulichkeit
Keine
Integrität
Keine
Verfügbarkeit
Hoch
Ausnutzungswahrscheinlichkeit innerhalb von 30 Tagen
0.1%
Perzentil
3e
Quelle: FIRST.org, aktualisiert am 23. September 2026.
Limit access to the interactive shell of the additional GNU/Linux subssytem to trusted personnel only.
Unsere eigene Einordnung und unser Kontext zu den obigen Quelldaten.
IACS-Radar-Einordnung
Unsere eigene Einordnung und unser Kontext zu dieser Schwachstelle — keine offizielle Quelle.
IACS-Radar-Prioritätswert
Basierend auf CVSS 5.5, EPSS 0.1%, industrielle Relevanz 55/100.
Kombiniert CVSS, EPSS, KEV-Status, industrielle Relevanz und Expositionsrelevanz — eine Ergänzung, kein Ersatz für die einzelnen Werte darunter und darüber.
Voraussetzungen für eine Ausnutzung
Operative Auswirkungen & Energierelevanz
Möglicher Verlust der Sicht auf oder der Kontrolle über den Prozess bei erfolgreicher Ausnutzung.
Als relevant für den Energiesektor eingestuft aufgrund von: Vermeld in een officiële CISA ICS Advisory, wat directe relevantie voor industriële besturingssystemen bevestigt. Der Hersteller „Siemens“ ist ein bekannter Lieferant von Ausrüstung für den Energiesektor.
Empfohlene defensive Maßnahmen
Industrieller Relevanzwert
Die Einstufung ist vorläufig; eine manuelle Überprüfung durch einen OT-Security-Analysten wird empfohlen.
Klassifiziert von IACS Radar-analysepijplijn (geautomatiseerd) am 24. September 2026.
IEC-62443-Zuordnung
Automatische IACS-Radar-Einordnung anhand der gemeldeten CWE-Schwächeklassifizierung; keine offizielle Zertifizierungsaussage.