CVE-2026-72390

Estado: RecibidaAlta (7.8)—

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

net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF

The teql master->slaves singly linked list is not protected against multiple writes. It can be mod'ed concurently from teql_master_xmit(), teql_dequeue(), teql_init() and teql_destroy() without holding any list lock or RCU protection.

zdi-disclosures@trendmicro.com has demonstrated that the qdisc is freed after an RCU grace period, but teql_master_xmit() running on another CPU can still hold a stale pointer into the list, resulting in a slab-use-after-free:

Leer descripción completaMostrar menos

The fix? Add a per-master slaves_lock spinlock that serializes all mutations of master->slaves and the NEXT_SLAVE() links in teql_destroy() and teql_qdisc_init(). teql_master_xmit() also takes the same slaves_lock around those updates. Annotate master->slaves and the per-slave ->next pointer with __rcu and use the appropriate RCU accessors everywhere they are touched: rcu_assign_pointer() on the writer side (under slaves_lock), rcu_dereference_protected() for the writer-side loads (also under slaves_lock), rcu_dereference_bh() for the loads in teql_master_xmit() and rtnl_dereference() for the loads in teql_master_open()/teql_master_mtu(), which run under RTNL. Pair this with rcu_read_lock_bh()/rcu_read_unlock_bh() around the list traversal in teql_master_xmit(), so that readers either observe a fully linked list or are deferred until the in-flight mutation completes. The two early-return paths in teql_master_xmit() are updated to release the RCU-bh read-side critical section before returning, since leaving it held would disable BH on that CPU for good.

Detalles técnicos trazas, registros y código del informe original

BUG: KASAN: slab-use-after-free in teql_master_xmit+0xf0f/0x16b0
Read of size 8 at addr ffff888013fb0440 by task poc/332
Freed 512-byte region [ffff888013fb0400, ffff888013fb0600) (kmalloc-512)

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: 6/10/2026

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 secundarioT1005 Data from Local Systemcollection60 %

Acceso local sin interacción del usuario (AV:L/UI:N/PR:L) permite escalada mediante race condition de memoria (slab-use-after-free) en kernel de Linux. Resulta en DoS por crash y potencial lectura de memoria.

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 Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

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)

Mostrar

{
  "id": "CVE-2026-72390",
  "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"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "03c67781254c574ae7fa75e881239a78473bdf42",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "735567bde7401f82b064f9f107b52ee1bf84ed8c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "11402e6e18e96df615cbcc58157818dd604b23ff",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "9b7d05cbaa60108642402100efa6aa288dd33023",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "b26aa9d993537a4c3167d8ceead3b7c69c3a0aac",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "e5b811fe793166aecc59b085c1b7c31262ef2316",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/sched/sch_teql.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.12",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sched/sch_teql.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:12.510",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/03c67781254c574ae7fa75e881239a78473bdf42",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/11402e6e18e96df615cbcc58157818dd604b23ff",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/735567bde7401f82b064f9f107b52ee1bf84ed8c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9b7d05cbaa60108642402100efa6aa288dd33023",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b26aa9d993537a4c3167d8ceead3b7c69c3a0aac",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e5b811fe793166aecc59b085c1b7c31262ef2316",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF\n\nThe teql master->slaves singly linked list is not protected against\nmultiple writes. It can be mod'ed concurently from teql_master_xmit(),\nteql_dequeue(), teql_init() and teql_destroy() without holding any list\nlock or RCU protection.\n\nzdi-disclosures@trendmicro.com has demonstrated that the qdisc is freed\nafter an RCU grace period, but teql_master_xmit() running on another\nCPU can still hold a stale pointer into the list, resulting in a\nslab-use-after-free:\n\nBUG: KASAN: slab-use-after-free in teql_master_xmit+0xf0f/0x16b0\nRead of size 8 at addr ffff888013fb0440 by task poc/332\nFreed 512-byte region [ffff888013fb0400, ffff888013fb0600) (kmalloc-512)\n\nThe fix?\nAdd a per-master slaves_lock spinlock that serializes all mutations of\nmaster->slaves and the NEXT_SLAVE() links in teql_destroy() and\nteql_qdisc_init(). teql_master_xmit() also takes the same slaves_lock\naround those updates.\nAnnotate master->slaves and the per-slave ->next pointer with __rcu and\nuse the appropriate RCU accessors everywhere they are touched:\nrcu_assign_pointer() on the writer side (under slaves_lock),\nrcu_dereference_protected() for the writer-side loads (also under\nslaves_lock), rcu_dereference_bh() for the loads in teql_master_xmit() and\nrtnl_dereference() for the loads in teql_master_open()/teql_master_mtu(),\nwhich run under RTNL.\nPair this with rcu_read_lock_bh()/rcu_read_unlock_bh() around the list\ntraversal in teql_master_xmit(), so that readers either observe a fully\nlinked list or are deferred until the in-flight mutation completes. The two\nearly-return paths in teql_master_xmit() are updated to release the RCU-bh\nread-side critical section before returning, since leaving it held would\ndisable BH on that CPU for good."
    }
  ],
  "lastModified": "2026-08-17T06:19:05.437",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}