CVE-2026-10655

{
  "id": "CVE-2026-10655",
  "sourceIdentifier": "[email protected]",
  "published": "2026-06-30T17:16:20.387",
  "lastModified": "2026-10-25T21:10:00.770",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The asynchronous SNTP client in Zephyr (subsys/net/lib/sntp/sntp.c, sntp_close_async) closed the UDP socket file descriptor directly from the calling thread immediately after detaching it from the network socket service, without synchronizing with the socket-service poll thread.\n\nThe socket service thread polls each socket via zvfs_poll, which (in zsock_poll_prepare_ctx) registers a k_poll_event pointing into the socket's net_context (&ctx->recv_q) and then blocks in k_poll without holding a reference or lock. net_context objects are allocated from a fixed pool (contexts[CONFIG_NET_MAX_CONTEXTS]) and reused after close.\n\nWhen sntp_close_async is invoked from a different thread than the poll thread (in the in-tree consumer subsys/net/lib/config/init_clock_sntp.c, the SNTP timeout handler runs on the system workqueue while the socket service thread is blocked in poll on the same fd), the close frees and may reuse the net_context while the poll thread still has a poller node linked into the freed object, resulting in a use-after-free / object confusion of kernel poll structures.\n\nThe SNTP timeout path is the normal no-response failure mode, so a network peer or off-path attacker who drops or delays the SNTP/NTP response can drive the racing close repeatedly (and periodically with NET_CONFIG_SNTP_INIT_RESYNC). The most likely consequence is a crash of the networking thread (denial of service), with potential memory corruption when the freed context slot is reallocated.\n\nThe fix defers the close to the socket service thread itself via net_socket_service_close (NET_SOCKET_SERVICE_CLOSE_SOCKETS), so the same thread that polls performs the close, eliminating the race. Affected releases: v4.2.0 through v4.4.0."
    },
    {
      "lang": "es",
      "value": "El cliente SNTP asíncrono en Zephyr (subsys/net/lib/sntp/sntp.c, sntp_close_async) cerró el descriptor de archivo del socket UDP directamente desde el hilo llamador inmediatamente después de desvincularlo del servicio de sockets de red, sin sincronizarse con el hilo de sondeo del servicio de sockets.\n\nEl hilo del servicio de sockets sondea cada socket a través de zvfs_poll, el cual (en zsock_poll_prepare_ctx) registra un k_poll_event apuntando al net_context del socket (&ctx  ->  recv_q) y luego se bloquea en k_poll sin mantener una referencia o un bloqueo. Los objetos net_context se asignan de un pool fijo (contexts[CONFIG_NET_MAX_CONTEXTS]) y se reutilizan después del cierre.\n\nCuando sntp_close_async es invocado desde un hilo diferente al hilo de sondeo (en el consumidor in-tree subsys/net/lib/config/init_clock_sntp.c, el gestor de tiempo de espera SNTP se ejecuta en la cola de trabajo del sistema mientras el hilo del servicio de sockets está bloqueado en el sondeo en el mismo fd), el cierre libera y puede reutilizar el net_context mientras el hilo de sondeo todavía tiene un nodo de sondeo vinculado al objeto liberado, lo que resulta en un uso después de liberación / confusión de objetos de las estructuras de sondeo del kernel.\n\nLa ruta de tiempo de espera SNTP es el modo de fallo normal sin respuesta, por lo que un par de red o un atacante fuera de ruta que descarta o retrasa la respuesta SNTP/NTP puede impulsar el cierre en carrera repetidamente (y periódicamente con NET_CONFIG_SNTP_INIT_RESYNC). La consecuencia más probable es un fallo del hilo de red (denegación de servicio), con potencial corrupción de memoria cuando el slot de contexto liberado es reasignado.\n\nLa solución aplaza el cierre al propio hilo del servicio de sockets a través de net_socket_service_close (NET_SOCKET_SERVICE_CLOSE_SOCKETS), por lo que el mismo hilo que sondea realiza el cierre, eliminando la condición de carrera. Versiones afectadas: v4.2.0 a v4.4.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "zephyrproject",
          "product": "zephyr",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "packageName": "zephyr",
          "programFiles": [
            "subsys/net/lib/sntp/sntp.c"
          ],
          "versions": [
            {
              "version": "4.2.0",
              "lessThan": "4.3.1",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "4.4.0",
              "lessThan": "4.4.2",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 4.2
      },
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-06-30T16:41:42.494668Z",
          "id": "CVE-2026-10655",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "4.2.0",
              "versionEndIncluding": "4.4.1",
              "matchCriteriaId": "B9DBA781-90DC-4697-9CB8-D922C4788E98"
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  "references": [
    {
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/ef47bdf328b4206ac3b3922ec09184f7a6f7412a",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-34wr-cg29-c4mw",
      "source": "[email protected]",
      "tags": [
        "Exploit",
        "Patch",
        "Vendor Advisory"
      ]
    }
  ]
}