ksmbd: fix use-after-free in durable v2 replay of active file handles_CVE-2026-23427

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in durable v2 replay of active file handles\n\nparse_durable_handle_context() unconditionally assigns dh_info->fp->conn\nto the current connection when handling a DURABLE_REQ_V2 context with\nSMB2_FLAGS_REPLAY_OPERATION. ksmbd_lookup_fd_cguid() does not filter by\nfp->conn, so it returns file handles that are already actively connected.\nThe unconditional overwrite replaces fp->conn, and when the overwriting\nconnection is subsequently freed, __ksmbd_close_fd() dereferences the\nstale fp->conn via spin_lock(&fp->conn->llist_lock), causing a\nuse-after-free.\n\nKASAN report:\n\n[    7.349357] ==================================================================\n[    7.349607] BUG: KASAN: slab-use-after-free in _raw_spin_lock+0x75/0xe0\n[    7.349811] Write of size 4 at addr ffff8881056ac18c by task kworker/1:2/108\n[    7.350010]\n[    7.350064] CPU: 1 UID: 0 PID: 108 Comm: kworker/1:2 Not tainted 7.0.0-rc3+ #58 PREEMPTLAZY\n[    7.350068] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[    7.350070] Workqueue: ksmbd-io handle_ksmbd_work\n[    7.350083] Call Trace:\n[    7.350087]  <TASK>\n[    7.350087]  dump_stack_lvl+0x64/0x80\n[    7.350094]  print_report+0xce/0x660\n[    7.350100]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    7.350101]  ? __pfx___mod_timer+0x10/0x10\n[    7.350106]  ? _raw_spin_lock+0x75/0xe0\n[    7.350108]  kasan_report+0xce/0x100\n[    7.350109]  ? _raw_spin_lock+0x75/0xe0\n[    7.350114]  kasan_check_range+0x105/0x1b0\n[    7.350116]  _raw_spin_lock+0x75/0xe0\n[    7.350118]  ? __pfx__raw_spin_lock+0x10/0x10\n[    7.350119]  ? __call_rcu_common.constprop.0+0x25e/0x780\n[    7.350125]  ? close_id_del_oplock+0x2cc/0x4e0\n[    7.350128]  __ksmbd_close_fd+0x27f/0xaf0\n[    7.350131]  ksmbd_close_fd+0x135/0x1b0\n[    7.350133]  smb2_close+0xb19/0x15b0\n[    7.350142]  ? __pfx_smb2_close+0x10/0x10\n[    7.350143]  ? xas_load+0x18/0x270\n[    7.350146]  ? _raw_spin_lock+0x84/0xe0\n[    7.350148]  ? __pfx__raw_spin_lock+0x10/0x10\n[    7.350150]  ? _raw_spin_unlock+0xe/0x30\n[    7.350151]  ? ksmbd_smb2_check_message+0xeb2/0x24c0\n[    7.350153]  ? ksmbd_tree_conn_lookup+0xcd/0xf0\n[    7.350154]  handle_ksmbd_work+0x40f/0x1080\n[    7.350156]  process_one_work+0x5fa/0xef0\n[    7.350162]  ? assign_work+0x122/0x3e0\n[    7.350163]  worker_thread+0x54b/0xf70\n[    7.350165]  ? __pfx_worker_thread+0x10/0x10\n[    7.350166]  kthread+0x346/0x470\n[    7.350170]  ? recalc_sigpending+0x19b/0x230\n[    7.350176]  ? __pfx_kthread+0x10/0x10\n[    7.350178]  ret_from_fork+0x4fb/0x6c0\n[    7.350183]  ? __pfx_ret_from_fork+0x10/0x10\n[    7.350185]  ? __switch_to+0x36c/0xbe0\n[    7.350188]  ? __pfx_kthread+0x10/0x10\n[    7.350190]  ret_from_fork_asm+0x1a/0x30\n[    7.350197]  </TASK>\n[    7.350197]\n[    7.355160] Allocated by task 123:\n[    7.355261]  kasan_save_stack+0x33/0x60\n[    7.355373]  kasan_save_track+0x14/0x30\n[    7.355484]  __kasan_kmalloc+0x8f/0xa0\n[    7.355593]  ksmbd_conn_alloc+0x44/0x6d0\n[    7.355711]  ksmbd_kthread_fn+0x243/0xd70\n[    7.355839]  kthread+0x346/0x470\n[    7.355942]  ret_from_fork+0x4fb/0x6c0\n[    7.356051]  ret_from_fork_asm+0x1a/0x30\n[    7.356164]\n[    7.356214] Freed by task 134:\n[    7.356305]  kasan_save_stack+0x33/0x60\n[    7.356416]  kasan_save_track+0x14/0x30\n[    7.356527]  kasan_save_free_info+0x3b/0x60\n[    7.356646]  __kasan_slab_free+0x43/0x70\n[    7.356761]  kfree+0x1ca/0x430\n[    7.356862]  ksmbd_tcp_disconnect+0x59/0xe0\n[    7.356993]  ksmbd_conn_handler_loop+0x77e/0xd40\n[    7.357138]  kthread+0x346/0x470\n[    7.357240]  ret_from_fork+0x4fb/0x6c0\n[    7.357350]  ret_from_fork_asm+0x1a/0x30\n[    7.357463]\n[    7.357513] The buggy address belongs to the object at ffff8881056ac000\n[    7.357513]  which belongs to the cache kmalloc-1k of size 1024\n[    7.357857] The buggy address is located 396 bytes inside of\n[    7.357857]  freed 1024-byte region \n---truncated---",
    "published": "2026-04-03T15:15:14.183Z",
    "modified": "2026-04-27T14:02:18.220Z",
    "type": "cve",
    "title": "ksmbd: fix use-after-free in durable v2 replay of active file handles",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/b0158d9d6f4ec5941e49a0b812735db2844f9975\nhttps://git.kernel.org/stable/c/568a25fd7bcdfb2790f7d42aa2a440dca4435c96\nhttps://git.kernel.org/stable/c/a5828c14a9e3d5eeed0bcc0a58f0f3fbca0cdcb2\nhttps://git.kernel.org/stable/c/9b0792c3eacf01e67f356d6ef9707b0ae5022419\nhttps://git.kernel.org/stable/c/b425e4d0eb321a1116ddbf39636333181675d8f4",
    "id": "CVE-2026-23427",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 8df4bcdb0a4232192b2445256c39b787d58ef14d\nLinux Linux c8efcc786146a951091588e5fa7e3c754850cb3c\nLinux Linux c8efcc786146a951091588e5fa7e3c754850cb3c\nLinux Linux c8efcc786146a951091588e5fa7e3c754850cb3c\nLinux Linux c8efcc786146a951091588e5fa7e3c754850cb3c\nLinux Linux 6.9",
    "sourceHref": "",
    "cvss": {
        "score": 9.8,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "8df4bcdb0a4232192b2445256c39b787d58ef14d",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}