GHSA-V45R-HFJF-MQ4Q
Vulnerability from github – Published: 2026-04-03 18:31 – Updated: 2026-04-23 21:31In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free of share_conf in compound request
smb2_get_ksmbd_tcon() reuses work->tcon in compound requests without validating tcon->t_state. ksmbd_tree_conn_lookup() checks t_state == TREE_CONNECTED on the initial lookup path, but the compound reuse path bypasses this check entirely.
If a prior command in the compound (SMB2_TREE_DISCONNECT) sets t_state to TREE_DISCONNECTED and frees share_conf via ksmbd_share_config_put(), subsequent commands dereference the freed share_conf through work->tcon->share_conf.
KASAN report:
[ 4.144653] ================================================================== [ 4.145059] BUG: KASAN: slab-use-after-free in smb2_write+0xc74/0xe70 [ 4.145415] Read of size 4 at addr ffff88810430c194 by task kworker/1:1/44 [ 4.145772] [ 4.145867] CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted 7.0.0-rc3+ #60 PREEMPTLAZY [ 4.145871] 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 [ 4.145875] Workqueue: ksmbd-io handle_ksmbd_work [ 4.145888] Call Trace: [ 4.145892] [ 4.145894] dump_stack_lvl+0x64/0x80 [ 4.145910] print_report+0xce/0x660 [ 4.145919] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 4.145928] ? smb2_write+0xc74/0xe70 [ 4.145931] kasan_report+0xce/0x100 [ 4.145934] ? smb2_write+0xc74/0xe70 [ 4.145937] smb2_write+0xc74/0xe70 [ 4.145939] ? __pfx_smb2_write+0x10/0x10 [ 4.145942] ? _raw_spin_unlock+0xe/0x30 [ 4.145945] ? ksmbd_smb2_check_message+0xeb2/0x24c0 [ 4.145948] ? smb2_tree_disconnect+0x31c/0x480 [ 4.145951] handle_ksmbd_work+0x40f/0x1080 [ 4.145953] process_one_work+0x5fa/0xef0 [ 4.145962] ? assign_work+0x122/0x3e0 [ 4.145964] worker_thread+0x54b/0xf70 [ 4.145967] ? __pfx_worker_thread+0x10/0x10 [ 4.145970] kthread+0x346/0x470 [ 4.145976] ? recalc_sigpending+0x19b/0x230 [ 4.145980] ? __pfx_kthread+0x10/0x10 [ 4.145984] ret_from_fork+0x4fb/0x6c0 [ 4.145992] ? __pfx_ret_from_fork+0x10/0x10 [ 4.145995] ? __switch_to+0x36c/0xbe0 [ 4.145999] ? __pfx_kthread+0x10/0x10 [ 4.146003] ret_from_fork_asm+0x1a/0x30 [ 4.146013] [ 4.146014] [ 4.149858] Allocated by task 44: [ 4.149953] kasan_save_stack+0x33/0x60 [ 4.150061] kasan_save_track+0x14/0x30 [ 4.150169] __kasan_kmalloc+0x8f/0xa0 [ 4.150274] ksmbd_share_config_get+0x1dd/0xdd0 [ 4.150401] ksmbd_tree_conn_connect+0x7e/0x600 [ 4.150529] smb2_tree_connect+0x2e6/0x1000 [ 4.150645] handle_ksmbd_work+0x40f/0x1080 [ 4.150761] process_one_work+0x5fa/0xef0 [ 4.150873] worker_thread+0x54b/0xf70 [ 4.150978] kthread+0x346/0x470 [ 4.151071] ret_from_fork+0x4fb/0x6c0 [ 4.151176] ret_from_fork_asm+0x1a/0x30 [ 4.151286] [ 4.151332] Freed by task 44: [ 4.151418] kasan_save_stack+0x33/0x60 [ 4.151526] kasan_save_track+0x14/0x30 [ 4.151634] kasan_save_free_info+0x3b/0x60 [ 4.151751] __kasan_slab_free+0x43/0x70 [ 4.151861] kfree+0x1ca/0x430 [ 4.151952] __ksmbd_tree_conn_disconnect+0xc8/0x190 [ 4.152088] smb2_tree_disconnect+0x1cd/0x480 [ 4.152211] handle_ksmbd_work+0x40f/0x1080 [ 4.152326] process_one_work+0x5fa/0xef0 [ 4.152438] worker_thread+0x54b/0xf70 [ 4.152545] kthread+0x346/0x470 [ 4.152638] ret_from_fork+0x4fb/0x6c0 [ 4.152743] ret_from_fork_asm+0x1a/0x30 [ 4.152853] [ 4.152900] The buggy address belongs to the object at ffff88810430c180 [ 4.152900] which belongs to the cache kmalloc-96 of size 96 [ 4.153226] The buggy address is located 20 bytes inside of [ 4.153226] freed 96-byte region [ffff88810430c180, ffff88810430c1e0) [ 4.153549] [ 4.153596] The buggy address belongs to the physical page: [ 4.153750] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810430ce80 pfn:0x10430c [ 4.154000] flags: 0x ---truncated---
{
"affected": [],
"aliases": [
"CVE-2026-23428"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-03T16:16:23Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of share_conf in compound request\n\nsmb2_get_ksmbd_tcon() reuses work-\u003etcon in compound requests without\nvalidating tcon-\u003et_state. ksmbd_tree_conn_lookup() checks t_state ==\nTREE_CONNECTED on the initial lookup path, but the compound reuse path\nbypasses this check entirely.\n\nIf a prior command in the compound (SMB2_TREE_DISCONNECT) sets t_state\nto TREE_DISCONNECTED and frees share_conf via ksmbd_share_config_put(),\nsubsequent commands dereference the freed share_conf through\nwork-\u003etcon-\u003eshare_conf.\n\nKASAN report:\n\n[ 4.144653] ==================================================================\n[ 4.145059] BUG: KASAN: slab-use-after-free in smb2_write+0xc74/0xe70\n[ 4.145415] Read of size 4 at addr ffff88810430c194 by task kworker/1:1/44\n[ 4.145772]\n[ 4.145867] CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted 7.0.0-rc3+ #60 PREEMPTLAZY\n[ 4.145871] 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[ 4.145875] Workqueue: ksmbd-io handle_ksmbd_work\n[ 4.145888] Call Trace:\n[ 4.145892] \u003cTASK\u003e\n[ 4.145894] dump_stack_lvl+0x64/0x80\n[ 4.145910] print_report+0xce/0x660\n[ 4.145919] ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[ 4.145928] ? smb2_write+0xc74/0xe70\n[ 4.145931] kasan_report+0xce/0x100\n[ 4.145934] ? smb2_write+0xc74/0xe70\n[ 4.145937] smb2_write+0xc74/0xe70\n[ 4.145939] ? __pfx_smb2_write+0x10/0x10\n[ 4.145942] ? _raw_spin_unlock+0xe/0x30\n[ 4.145945] ? ksmbd_smb2_check_message+0xeb2/0x24c0\n[ 4.145948] ? smb2_tree_disconnect+0x31c/0x480\n[ 4.145951] handle_ksmbd_work+0x40f/0x1080\n[ 4.145953] process_one_work+0x5fa/0xef0\n[ 4.145962] ? assign_work+0x122/0x3e0\n[ 4.145964] worker_thread+0x54b/0xf70\n[ 4.145967] ? __pfx_worker_thread+0x10/0x10\n[ 4.145970] kthread+0x346/0x470\n[ 4.145976] ? recalc_sigpending+0x19b/0x230\n[ 4.145980] ? __pfx_kthread+0x10/0x10\n[ 4.145984] ret_from_fork+0x4fb/0x6c0\n[ 4.145992] ? __pfx_ret_from_fork+0x10/0x10\n[ 4.145995] ? __switch_to+0x36c/0xbe0\n[ 4.145999] ? __pfx_kthread+0x10/0x10\n[ 4.146003] ret_from_fork_asm+0x1a/0x30\n[ 4.146013] \u003c/TASK\u003e\n[ 4.146014]\n[ 4.149858] Allocated by task 44:\n[ 4.149953] kasan_save_stack+0x33/0x60\n[ 4.150061] kasan_save_track+0x14/0x30\n[ 4.150169] __kasan_kmalloc+0x8f/0xa0\n[ 4.150274] ksmbd_share_config_get+0x1dd/0xdd0\n[ 4.150401] ksmbd_tree_conn_connect+0x7e/0x600\n[ 4.150529] smb2_tree_connect+0x2e6/0x1000\n[ 4.150645] handle_ksmbd_work+0x40f/0x1080\n[ 4.150761] process_one_work+0x5fa/0xef0\n[ 4.150873] worker_thread+0x54b/0xf70\n[ 4.150978] kthread+0x346/0x470\n[ 4.151071] ret_from_fork+0x4fb/0x6c0\n[ 4.151176] ret_from_fork_asm+0x1a/0x30\n[ 4.151286]\n[ 4.151332] Freed by task 44:\n[ 4.151418] kasan_save_stack+0x33/0x60\n[ 4.151526] kasan_save_track+0x14/0x30\n[ 4.151634] kasan_save_free_info+0x3b/0x60\n[ 4.151751] __kasan_slab_free+0x43/0x70\n[ 4.151861] kfree+0x1ca/0x430\n[ 4.151952] __ksmbd_tree_conn_disconnect+0xc8/0x190\n[ 4.152088] smb2_tree_disconnect+0x1cd/0x480\n[ 4.152211] handle_ksmbd_work+0x40f/0x1080\n[ 4.152326] process_one_work+0x5fa/0xef0\n[ 4.152438] worker_thread+0x54b/0xf70\n[ 4.152545] kthread+0x346/0x470\n[ 4.152638] ret_from_fork+0x4fb/0x6c0\n[ 4.152743] ret_from_fork_asm+0x1a/0x30\n[ 4.152853]\n[ 4.152900] The buggy address belongs to the object at ffff88810430c180\n[ 4.152900] which belongs to the cache kmalloc-96 of size 96\n[ 4.153226] The buggy address is located 20 bytes inside of\n[ 4.153226] freed 96-byte region [ffff88810430c180, ffff88810430c1e0)\n[ 4.153549]\n[ 4.153596] The buggy address belongs to the physical page:\n[ 4.153750] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810430ce80 pfn:0x10430c\n[ 4.154000] flags: 0x\n---truncated---",
"id": "GHSA-v45r-hfjf-mq4q",
"modified": "2026-04-23T21:31:18Z",
"published": "2026-04-03T18:31:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23428"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7f7468fd2a7554cea91b7d430335a3dbf01dcc09"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/806f13752652216db0c309392b4db3e64eeed4f2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a5929c2020ce54e1dcbd1078c0f30b8aaf73c105"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c33615f995aee80657b9fdfbc4ee7f49c2bd733d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c742b46a153d3ff95ff0825ab1950c87b9e14470"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d08417981155883068b7260d9500ca306a03edac"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eae0dc86f71e6f3294c0cd7ffc05039258d243af"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.