CVE-2026-89508

Estado: RecibidaAlta (7.8)—

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

RDMA/ucma: Lock the handler in ucma_set_ib_path()

ucma_set_ib_path() calls ucma_event_handler() straight from the write() path, without the handler lock that keeps ctx->file stable while a uevent is queued. The handler re-reads ctx->file for every dereference:

A concurrent ucma_migrate_id() reassigns ctx->file while the SET_OPTION caller sleeps in mutex_lock(), so the list_add_tail() lands on file B's event_list while only file A's mutex is held, racing every other user of that list:

The freed object is a ucma_event that another thread dequeued from file B's list under file B's mutex. File A's mut is left held on top of that, wedging its next writer in uninterruptible sleep.

Leer descripción completaMostrar menos

This path needs a bound and address-resolved cm_id, so it requires an RDMA device to be present.

Take the handler lock around the call.

Detalles técnicos trazas, registros y código del informe original

	mutex_lock(&ctx->file->mut);			/* file A */
	list_add_tail(&uevent->list, &ctx->file->event_list);	/* file B */
	mutex_unlock(&ctx->file->mut);			/* file B */
	wake_up_interruptible(&ctx->file->poll_wait);	/* file B */

  BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x1aa/0x1c0
  Read of size 8 at addr ffff888153c6a418 by task poc_corr/486
  Call Trace:
   __list_add_valid_or_report+0x1aa/0x1c0
   ucma_event_handler+0x1be/0xc00
   ucma_set_ib_path+0x45e/0x710
   ucma_set_option+0x32e/0x590
   ucma_write+0x1f9/0x330
  Allocated by task 505:
   ucma_write_cm_event+0x1a1/0x660
  Freed by task 505:
   kfree+0x1da/0x4c0
   ucma_get_event+0x5d5/0x7e0

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.17%
Percentil entre todas las CVEs puntuadas: 6
Fecha de la puntuación: 4/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1565.001 Stored Data Manipulationimpact60 %

Vulnerabilidad local (AV:L/PR:L) que causa race condition en kernel RDMA. Permite DoS (wedging writers) y corrupción de memoria (use-after-free), requiriendo escalada de privilegios para explotar.

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

Threat Intelligence Program Restrict File and Directory Permissions Remote Data Storage Filter Network Traffic Execution Prevention Encrypt Sensitive Information

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-89508",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
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        "impactScore": 5.9,
        "exploitabilityScore": 1.8
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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          "programFiles": [
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              "status": "unaffected",
              "version": "6.1.188",
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              "version": "6.6.157",
              "versionType": "semver",
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              "version": "6.12.109",
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              "versionType": "original_commit_for_fix",
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          ],
          "programFiles": [
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          ],
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        }
      ]
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  ],
  "published": "2026-09-11T20:19:33.143",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/28ac2dd416482d1c763c4af5d61af465b387fb50",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/ucma: Lock the handler in ucma_set_ib_path()\n\nucma_set_ib_path() calls ucma_event_handler() straight from the write()\npath, without the handler lock that keeps ctx->file stable while a uevent\nis queued.  The handler re-reads ctx->file for every dereference:\n\n\tmutex_lock(&ctx->file->mut);\t\t\t/* file A */\n\tlist_add_tail(&uevent->list, &ctx->file->event_list);\t/* file B */\n\tmutex_unlock(&ctx->file->mut);\t\t\t/* file B */\n\twake_up_interruptible(&ctx->file->poll_wait);\t/* file B */\n\nA concurrent ucma_migrate_id() reassigns ctx->file while the SET_OPTION\ncaller sleeps in mutex_lock(), so the list_add_tail() lands on file B's\nevent_list while only file A's mutex is held, racing every other user of\nthat list:\n\n  BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x1aa/0x1c0\n  Read of size 8 at addr ffff888153c6a418 by task poc_corr/486\n  Call Trace:\n   __list_add_valid_or_report+0x1aa/0x1c0\n   ucma_event_handler+0x1be/0xc00\n   ucma_set_ib_path+0x45e/0x710\n   ucma_set_option+0x32e/0x590\n   ucma_write+0x1f9/0x330\n  Allocated by task 505:\n   ucma_write_cm_event+0x1a1/0x660\n  Freed by task 505:\n   kfree+0x1da/0x4c0\n   ucma_get_event+0x5d5/0x7e0\n\nThe freed object is a ucma_event that another thread dequeued from file B's\nlist under file B's mutex.  File A's mut is left held on top of that,\nwedging its next writer in uninterruptible sleep.\n\nThis path needs a bound and address-resolved cm_id, so it requires an RDMA\ndevice to be present.\n\nTake the handler lock around the call."
    }
  ],
  "lastModified": "2026-09-14T13:19:07.370",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}