FKIE_CVE-2026-23393

Vulnerability from fkie_nvd - Published: 2026-03-25 11:16 - Updated: 2026-04-24 18:39
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: bridge: cfm: Fix race condition in peer_mep deletion When a peer MEP is being deleted, cancel_delayed_work_sync() is called on ccm_rx_dwork before freeing. However, br_cfm_frame_rx() runs in softirq context under rcu_read_lock (without RTNL) and can re-schedule ccm_rx_dwork via ccm_rx_timer_start() between cancel_delayed_work_sync() returning and kfree_rcu() being called. The following is a simple race scenario: cpu0 cpu1 mep_delete_implementation() cancel_delayed_work_sync(ccm_rx_dwork); br_cfm_frame_rx() // peer_mep still in hlist if (peer_mep->ccm_defect) ccm_rx_timer_start() queue_delayed_work(ccm_rx_dwork) hlist_del_rcu(&peer_mep->head); kfree_rcu(peer_mep, rcu); ccm_rx_work_expired() // on freed peer_mep To prevent this, cancel_delayed_work_sync() is replaced with disable_delayed_work_sync() in both peer MEP deletion paths, so that subsequent queue_delayed_work() calls from br_cfm_frame_rx() are silently rejected. The cc_peer_disable() helper retains cancel_delayed_work_sync() because it is also used for the CC enable/disable toggle path where the work must remain re-schedulable.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1fd81151f65927fd9edb8ecd12ad45527dbbe5abPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3715a00855316066cdda69d43648336367422127Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d8f35767bacb3c7769d470a41cf161e3f3c07e70Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e89dbd2736a45f0507949af4748cbbf3ff793146Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 5.11
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: cfm: Fix race condition in peer_mep deletion\n\nWhen a peer MEP is being deleted, cancel_delayed_work_sync() is called\non ccm_rx_dwork before freeing. However, br_cfm_frame_rx() runs in\nsoftirq context under rcu_read_lock (without RTNL) and can re-schedule\nccm_rx_dwork via ccm_rx_timer_start() between cancel_delayed_work_sync()\nreturning and kfree_rcu() being called.\n\nThe following is a simple race scenario:\n\n           cpu0                                     cpu1\n\nmep_delete_implementation()\n  cancel_delayed_work_sync(ccm_rx_dwork);\n                                           br_cfm_frame_rx()\n                                             // peer_mep still in hlist\n                                             if (peer_mep-\u003eccm_defect)\n                                               ccm_rx_timer_start()\n                                                 queue_delayed_work(ccm_rx_dwork)\n  hlist_del_rcu(\u0026peer_mep-\u003ehead);\n  kfree_rcu(peer_mep, rcu);\n                                           ccm_rx_work_expired()\n                                             // on freed peer_mep\n\nTo prevent this, cancel_delayed_work_sync() is replaced with\ndisable_delayed_work_sync() in both peer MEP deletion paths, so\nthat subsequent queue_delayed_work() calls from br_cfm_frame_rx()\nare silently rejected.\n\nThe cc_peer_disable() helper retains cancel_delayed_work_sync()\nbecause it is also used for the CC enable/disable toggle path where\nthe work must remain re-schedulable."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\n\nbridge: cfm: Correcci\u00f3n de condici\u00f3n de carrera en la eliminaci\u00f3n de peer_mep\n\nCuando se est\u00e1 eliminando un MEP par, se llama a cancel_delayed_work_sync() en ccm_rx_dwork antes de la liberaci\u00f3n. Sin embargo, br_cfm_frame_rx() se ejecuta en contexto de softirq bajo rcu_read_lock (sin RTNL) y puede reprogramar ccm_rx_dwork a trav\u00e9s de ccm_rx_timer_start() entre el retorno de cancel_delayed_work_sync() y la llamada a kfree_rcu().\n\nEl siguiente es un escenario de condici\u00f3n de carrera simple:\n\n           cpu0                                     cpu1\n\nmep_delete_implementation()\n  cancel_delayed_work_sync(ccm_rx_dwork);\n                                           br_cfm_frame_rx()\n                                             // peer_mep todav\u00eda en hlist\n                                             if (peer_mep-\u0026gt;ccm_defect)\n                                               ccm_rx_timer_start()\n                                                 queue_delayed_work(ccm_rx_dwork)\n  hlist_del_rcu(\u0026amp;peer_mep-\u0026gt;head);\n  kfree_rcu(peer_mep, rcu);\n                                           ccm_rx_work_expired()\n                                             // en peer_mep liberado\n\nPara evitar esto, cancel_delayed_work_sync() se reemplaza por disable_delayed_work_sync() en ambas rutas de eliminaci\u00f3n de MEP par, de modo que las llamadas posteriores a queue_delayed_work() desde br_cfm_frame_rx() sean rechazadas silenciosamente.\n\nLa funci\u00f3n auxiliar cc_peer_disable() mantiene cancel_delayed_work_sync() porque tambi\u00e9n se utiliza para la ruta de alternancia de habilitaci\u00f3n/deshabilitaci\u00f3n de CC donde el trabajo debe permanecer reprogramable."
    }
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  "id": "CVE-2026-23393",
  "lastModified": "2026-04-24T18:39:39.577",
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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          "value": "CWE-362"
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