CVE-2026-89561

Estado: RecibidaAlta (7.5)—

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

ipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv()

ipv6_rpl_srh_rcv() dereferences idev from __in6_dev_get() without a NULL check when reading idev->cnf.rpl_seg_enabled.

When the device's MTU drops below IPV6_MIN_MTU, addrconf_ifdown() clears dev->ip6_ptr through RCU_INIT_POINTER(). A packet that passed the idev check in ip6_rcv_core() can then reach ipv6_rpl_srh_rcv() with dev->ip6_ptr already NULL.

Reproduced by flooding the receiving interface with ping6 traffic while flapping its MTU between 1500 and 1200:

Both ipv6_rpl_srh_rcv() and ipv6_srh_rcv() are called only from ipv6_rthdr_rcv(), which already has an idev lookup.

Leer descripción completaMostrar menos

Fix the NULL dereference on the RPL path by checking idev in ipv6_rthdr_rcv(), before it calls either function. The callees take idev as an argument and no longer call __in6_dev_get(), so the packet is now dropped in one place, with SKB_DROP_REASON_IPV6DISABLED on both paths.

Detalles técnicos trazas, registros y código del informe original

 BUG: KASAN: null-ptr-deref in ipv6_rpl_srh_rcv+0xb3/0x1070
 Read of size 4 at addr 00000000000006b4 by task ping6/394

 CPU: 2 UID: 0 PID: 394 Comm: ping6 Not tainted 7.2.0-rc7-micro-vm-dev-00095-g24ef02f934ee #240 PREEMPT(full)
 Call Trace:
  <IRQ>
  kasan_report+0xc6/0x100
  ipv6_rpl_srh_rcv+0xb3/0x1070
  ip6_protocol_deliver_rcu+0x759/0x9a0
  ip6_input_finish+0xa8/0x1b0
  ip6_input+0xe1/0x490
  ipv6_rcv+0x33d/0x460
  __netif_receive_skb_one_core+0xd6/0x130
  process_backlog+0x2cc/0xa00
  __napi_poll.constprop.0+0x56/0x270
  net_rx_action+0x327/0x730
  handle_softirqs+0x11e/0x630
  do_softirq+0xb3/0xf0
  </IRQ>

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.44%
Percentil entre todas las CVEs puntuadas: 36
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

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-2026-89561",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "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": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3",
              "lessThan": "e7123e10c86eb88eaa90537dd1f232706de2d308",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3",
              "lessThan": "63f50e9f90d0287ad66a0955ebfc2d3a9c044a1c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3",
              "lessThan": "eab3a917cdcb182542a3aac6a0d2d30659ca9821",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3",
              "lessThan": "f826df95332c07380206dbd54178b6eefb311aba",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/ipv6/exthdrs.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.7",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/ipv6/exthdrs.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:39.933",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/63f50e9f90d0287ad66a0955ebfc2d3a9c044a1c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e7123e10c86eb88eaa90537dd1f232706de2d308",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/eab3a917cdcb182542a3aac6a0d2d30659ca9821",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f826df95332c07380206dbd54178b6eefb311aba",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: rpl: fix NULL dereference of idev in ipv6_rpl_srh_rcv()\n\nipv6_rpl_srh_rcv() dereferences idev from __in6_dev_get() without a NULL\ncheck when reading idev->cnf.rpl_seg_enabled.\n\nWhen the device's MTU drops below IPV6_MIN_MTU, addrconf_ifdown() clears\ndev->ip6_ptr through RCU_INIT_POINTER(). A packet that passed the idev\ncheck in ip6_rcv_core() can then reach ipv6_rpl_srh_rcv() with\ndev->ip6_ptr already NULL.\n\nReproduced by flooding the receiving interface with ping6 traffic while\nflapping its MTU between 1500 and 1200:\n\n BUG: KASAN: null-ptr-deref in ipv6_rpl_srh_rcv+0xb3/0x1070\n Read of size 4 at addr 00000000000006b4 by task ping6/394\n\n CPU: 2 UID: 0 PID: 394 Comm: ping6 Not tainted 7.2.0-rc7-micro-vm-dev-00095-g24ef02f934ee #240 PREEMPT(full)\n Call Trace:\n  <IRQ>\n  kasan_report+0xc6/0x100\n  ipv6_rpl_srh_rcv+0xb3/0x1070\n  ip6_protocol_deliver_rcu+0x759/0x9a0\n  ip6_input_finish+0xa8/0x1b0\n  ip6_input+0xe1/0x490\n  ipv6_rcv+0x33d/0x460\n  __netif_receive_skb_one_core+0xd6/0x130\n  process_backlog+0x2cc/0xa00\n  __napi_poll.constprop.0+0x56/0x270\n  net_rx_action+0x327/0x730\n  handle_softirqs+0x11e/0x630\n  do_softirq+0xb3/0xf0\n  </IRQ>\n\nBoth ipv6_rpl_srh_rcv() and ipv6_srh_rcv() are called only from\nipv6_rthdr_rcv(), which already has an idev lookup.\n\nFix the NULL dereference on the RPL path by checking idev in\nipv6_rthdr_rcv(), before it calls either function. The callees take idev as\nan argument and no longer call __in6_dev_get(), so the packet is now\ndropped in one place, with SKB_DROP_REASON_IPV6DISABLED on both paths."
    }
  ],
  "lastModified": "2026-09-21T14:17:23.290",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}