CVE-2026-46325

Estado: AnalizadaCrítica (9.8)—

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

RDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE

The current implementation incorrectly handles memory regions (MRs) with page sizes different from the system PAGE_SIZE. The core issue is that rxe_set_page() is called with mr->page_size step increments, but the page_list stores individual struct page pointers, each representing PAGE_SIZE of memory.

ib_sg_to_page() has ensured that when i>=1 either a) SG[i-1].dma_end and SG[i].dma_addr are contiguous or b) SG[i-1].dma_end and SG[i].dma_addr are mr->page_size aligned.

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This leads to incorrect iova-to-va conversion in scenarios:

Yi Zhang reported a kernel panic[1] years ago related to this defect.

Solution: 1. Replace xarray with pre-allocated rxe_mr_page array for sequential indexing (all MR page indices are contiguous) 2. Each rxe_mr_page stores both struct page* and offset within the system page 3. Handle MR page_size != PAGE_SIZE relationships: - page_size > PAGE_SIZE: Split MR pages into multiple system pages - page_size <= PAGE_SIZE: Store offset within system page 4. Add boundary checks and compatibility validation

This ensures correct iova-to-va conversion regardless of MR page size and system PAGE_SIZE relationship, while improving performance through array-based sequential access.

Tests on 4K and 64K PAGE_SIZE hosts: - rdma-core/pytests $ ./build/bin/run_tests.py --dev eth0_rxe - blktest: $ TIMEOUT=30 QUICK_RUN=1 USE_RXE=1 NVMET_TRTYPES=rdma ./check nvme srp rnbd

[1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@mail.gmail.com/T/

Detalles técnicos trazas, registros y código del informe original

1) page_size < PAGE_SIZE (e.g., MR: 4K, system: 64K):
   ibmr->iova = 0x181800
   sg[0]: dma_addr=0x181800, len=0x800
   sg[1]: dma_addr=0x173000, len=0x1000

   Access iova = 0x181800 + 0x810 = 0x182010
   Expected VA: 0x173010 (second SG, offset 0x10)
   Before fix:
     - index = (0x182010 >> 12) - (0x181800 >> 12) = 1
     - page_offset = 0x182010 & 0xFFF = 0x10
     - xarray[1] stores system page base 0x170000
     - Resulting VA: 0x170000 + 0x10 = 0x170010 (wrong)

2) page_size > PAGE_SIZE (e.g., MR: 64K, system: 4K):
   ibmr->iova = 0x18f800
   sg[0]: dma_addr=0x18f800, len=0x800
   sg[1]: dma_addr=0x170000, len=0x1000

   Access iova = 0x18f800 + 0x810 = 0x190010
   Expected VA: 0x170010 (second SG, offset 0x10)
   Before fix:
     - index = (0x190010 >> 16) - (0x18f800 >> 16) = 1
     - page_offset = 0x190010 & 0xFFFF = 0x10
     - xarray[1] stores system page for dma_addr 0x170000
     - Resulting VA: system page of 0x170000 + 0x10 = 0x170010 (wrong)

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 9.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.35%
Percentil entre todas las CVEs puntuadas: 26
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access75 %
Impacto principalT1499.004 Application or System Exploitationimpact85 %

Vector CVSS AV:N/AC:L/PR:N/UI:N indica explotación remota sin autenticación (T1190). El defecto en conversión iova-to-va en RDMA/rxe permite DoS (panic del kernel) y potencialmente escalada al ejecutarse en kernel. Crítico en Linux.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

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Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

NVD-CWE-noinfo

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-46325",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
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          "product": "Linux",
          "versions": [
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              "lessThan": "12985e5915a0b8354796efadaaeb201eed115377",
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            {
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              "version": "0e443760b8b7b1e6723f4408afa056b2bc4fea12",
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          "programFiles": [
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            "drivers/infiniband/sw/rxe/rxe_verbs.h"
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              "version": "7.0",
              "versionType": "original_commit_for_fix",
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          "programFiles": [
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            "drivers/infiniband/sw/rxe/rxe_verbs.h"
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  "published": "2026-06-09T14:16:42.177",
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      "tags": [
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          "value": "NVD-CWE-noinfo"
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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE\n\nThe current implementation incorrectly handles memory regions (MRs) with\npage sizes different from the system PAGE_SIZE. The core issue is that\nrxe_set_page() is called with mr->page_size step increments, but the\npage_list stores individual struct page pointers, each representing\nPAGE_SIZE of memory.\n\nib_sg_to_page() has ensured that when i>=1 either\na) SG[i-1].dma_end and SG[i].dma_addr are contiguous\nor\nb) SG[i-1].dma_end and SG[i].dma_addr are mr->page_size aligned.\n\nThis leads to incorrect iova-to-va conversion in scenarios:\n\n1) page_size < PAGE_SIZE (e.g., MR: 4K, system: 64K):\n   ibmr->iova = 0x181800\n   sg[0]: dma_addr=0x181800, len=0x800\n   sg[1]: dma_addr=0x173000, len=0x1000\n\n   Access iova = 0x181800 + 0x810 = 0x182010\n   Expected VA: 0x173010 (second SG, offset 0x10)\n   Before fix:\n     - index = (0x182010 >> 12) - (0x181800 >> 12) = 1\n     - page_offset = 0x182010 & 0xFFF = 0x10\n     - xarray[1] stores system page base 0x170000\n     - Resulting VA: 0x170000 + 0x10 = 0x170010 (wrong)\n\n2) page_size > PAGE_SIZE (e.g., MR: 64K, system: 4K):\n   ibmr->iova = 0x18f800\n   sg[0]: dma_addr=0x18f800, len=0x800\n   sg[1]: dma_addr=0x170000, len=0x1000\n\n   Access iova = 0x18f800 + 0x810 = 0x190010\n   Expected VA: 0x170010 (second SG, offset 0x10)\n   Before fix:\n     - index = (0x190010 >> 16) - (0x18f800 >> 16) = 1\n     - page_offset = 0x190010 & 0xFFFF = 0x10\n     - xarray[1] stores system page for dma_addr 0x170000\n     - Resulting VA: system page of 0x170000 + 0x10 = 0x170010 (wrong)\n\nYi Zhang reported a kernel panic[1] years ago related to this defect.\n\nSolution:\n1. Replace xarray with pre-allocated rxe_mr_page array for sequential\n   indexing (all MR page indices are contiguous)\n2. Each rxe_mr_page stores both struct page* and offset within the\n   system page\n3. Handle MR page_size != PAGE_SIZE relationships:\n   - page_size > PAGE_SIZE: Split MR pages into multiple system pages\n   - page_size <= PAGE_SIZE: Store offset within system page\n4. Add boundary checks and compatibility validation\n\nThis ensures correct iova-to-va conversion regardless of MR page size\nand system PAGE_SIZE relationship, while improving performance through\narray-based sequential access.\n\nTests on 4K and 64K PAGE_SIZE hosts:\n- rdma-core/pytests\n  $ ./build/bin/run_tests.py  --dev eth0_rxe\n- blktest:\n  $ TIMEOUT=30 QUICK_RUN=1 USE_RXE=1 NVMET_TRTYPES=rdma ./check nvme srp rnbd\n\n[1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@mail.gmail.com/T/"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nRDMA/rxe: Corrección de la conversión iova-a-va para tamaños de página de MR != PAGE_SIZE\n\nLa implementación actual maneja incorrectamente las regiones de memoria (MRs) con tamaños de página diferentes al PAGE_SIZE del sistema. El problema central es que rxe_set_page() se llama con incrementos de paso mr->page_size, pero la page_list almacena punteros individuales a struct page, cada uno representando PAGE_SIZE de memoria.\n\nib_sg_to_page() ha asegurado que cuando i>=1, o bien a) SG[i-1].dma_end y SG[i].dma_addr son contiguos o b) SG[i-1].dma_end y SG[i].dma_addr están alineados con mr->page_size.\n\nEsto lleva a una conversión iova-a-va incorrecta en los siguientes escenarios:\n\n1) page_size < PAGE_SIZE (ej., MR: 4K, sistema: 64K):\n   ibmr->iova = 0x181800\n   sg[0]: dma_addr=0x181800, len=0x800\n   sg[1]: dma_addr=0x173000, len=0x1000\n\n   Acceso iova = 0x181800 + 0x810 = 0x182010\n   VA esperada: 0x173010 (segundo SG, desplazamiento 0x10)\n   Antes de la corrección:\n     - índice = (0x182010 >> 12) - (0x181800 >> 12) = 1\n     - page_offset = 0x182010 & 0xFFF = 0x10\n     - xarray[1] almacena la base de página del sistema 0x170000\n     - VA resultante: 0x170000 + 0x10 = 0x170010 (incorrecto)\n\n2) page_size > PAGE_SIZE (ej., MR: 64K, sistema: 4K):\n   ibmr->iova = 0x18f800\n   sg[0]: dma_addr=0x18f800, len=0x800\n   sg[1]: dma_addr=0x170000, len=0x1000\n\n   Acceso iova = 0x18f800 + 0x810 = 0x190010\n   VA esperada: 0x170010 (segundo SG, desplazamiento 0x10)\n   Antes de la corrección:\n     - índice = (0x190010 >> 16) - (0x18f800 >> 16) = 1\n     - page_offset = 0x190010 & 0xFFFF = 0x10\n     - xarray[1] almacena la página del sistema para dma_addr 0x170000\n     - VA resultante: página del sistema de 0x170000 + 0x10 = 0x170010 (incorrecto)\n\nYi Zhang informó de un kernel panic[1] hace años relacionado con este defecto.\n\nSolución:\n1. Reemplazar xarray con un array rxe_mr_page preasignado para indexación secuencial (todos los índices de página de MR son contiguos)\n2. Cada rxe_mr_page almacena tanto struct page como el desplazamiento dentro de la página del sistema\n3. Manejar las relaciones MR page_size != PAGE_SIZE:\n   - page_size > PAGE_SIZE: Dividir las páginas de MR en múltiples páginas del sistema\n   - page_size <= PAGE_SIZE: Almacenar el desplazamiento dentro de la página del sistema\n4. Añadir comprobaciones de límites y validación de compatibilidad\n\nEsto asegura una conversión iova-a-va correcta independientemente del tamaño de página de MR y la relación PAGE_SIZE del sistema, al tiempo que mejora el rendimiento mediante el acceso secuencial basado en arrays.\n\nPruebas en hosts con PAGE_SIZE de 4K y 64K:\n- rdma-core/pytests\n  $ ./build/bin/run_tests.py  --dev eth0_rxe\n- blktest:\n  $ TIMEOUT=30 QUICK_RUN=1 USE_RXE=1 NVMET_TRTYPES=rdma ./check nvme srp rnbd\n\n[1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@mail.gmail.com/T/"
    }
  ],
  "lastModified": "2026-07-23T08:10:00.137",
  "configurations": [
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