ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE conn->preauth_info is shared connection state (struct preauth_integrity_info, kmalloc-96) that is allocated and freed by the SMB2 NEGOTIATE handler and read by the response send path. smb2_handle_negotiate() allocates conn->preauth_info, and on a deassemble_neg_contexts() failure kfrees it and sets it to NULL. Both the allocation and the free/NULL happen under ksmbd_conn_lock(conn) (the connection srv_mutex), which is held across the whole handler body. The response send path smb3_preauth_hash_rsp(), called from the send: block of __handle_ksmbd_work(), reads conn->preauth_info and dereferences conn->preauth_info->Preauth_HashValue (via ksmbd_gen_preauth_integrity_hash()) without taking conn_lock. When a client drives two SMB2 NEGOTIATE requests on the same connection, one worker can free conn->preauth_info on the failing-negotiate path while a concurrent send-path worker is reading it, producing a slab use-after-free read (KASAN-confirmed). The send-path read tested conn->preauth_info for NULL but raced with the free that occurs between the NULL check and the dereference, so the NULL guard alone does not close the window. Serialize the NEGOTIATE-branch read in smb3_preauth_hash_rsp() under ksmbd_conn_lock(conn) and re-check conn->preauth_info inside the lock. Because the negotiate handler holds conn_lock across its kfree + NULL assi
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.15.212, 6.1.178, 6.12.97, 6.18.40, 6.6.145, 7.1.5
- CVEs
- CVE-2026-72422
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 28 Oct 2026, 08:57 UTC · Revision 1
Source evidence
ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE
core-osv · Original sourcePublished 15 Aug 2026, 05:56 UTC
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE conn->preauth_info is shared connection state (struct preauth_integrity_info, kmalloc-96) that is allocated and freed by the SMB2 NEGOTIATE handler and read by the response send path. smb2_handle_negotiate() allocates conn->preauth_info, and on a deassemble_neg_contexts() failure kfrees it and sets it to NULL. Both the allocation and the free/NULL happen under ksmbd_conn_lock(conn) (the connection srv_mutex), which is held across the whole handler body. The response send path smb3_preauth_hash_rsp(), called from the send: block of __handle_ksmbd_work(), reads conn->preauth_info and dereferences conn->preauth_info->Preauth_HashValue (via ksmbd_gen_preauth_integrity_hash()) without taking conn_lock. When a client drives two SMB2 NEGOTIATE requests on the same connection, one worker can free conn->preauth_info on the failing-negotiate path while a concurrent send-path worker is reading it, producing a slab use-after-free read (KASAN-confirmed). The send-path read tested conn->preauth_info for NULL but raced with the free that occurs between the NULL check and the dereference, so the NULL guard alone does not close the window. Serialize the NEGOTIATE-branch read in smb3_preauth_hash_rsp() under ksmbd_conn_lock(conn) and re-check conn->preauth_info inside the lock. Because the negotiate handler holds conn_lock across its kfree + NULL assi
osv:CVE-2026-72422
Kernel
Fixed versions: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5
Complete source record
{
"id": "616aa3804b320737b387d8ccec2d2b8b35aaf2baf671a69f565859862eb1ba55",
"url": "https://osv.dev/vulnerability/CVE-2026-72422",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE",
"summary": "In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE conn->preauth_info is shared connection state (struct preauth_integrity_info, kmalloc-96) that is allocated and freed by the SMB2 NEGOTIATE handler and read by the response send path. smb2_handle_negotiate() allocates conn->preauth_info, and on a deassemble_neg_contexts() failure kfrees it and sets it to NULL. Both the allocation and the free/NULL happen under ksmbd_conn_lock(conn) (the connection srv_mutex), which is held across the whole handler body. The response send path smb3_preauth_hash_rsp(), called from the send: block of __handle_ksmbd_work(), reads conn->preauth_info and dereferences conn->preauth_info->Preauth_HashValue (via ksmbd_gen_preauth_integrity_hash()) without taking conn_lock. When a client drives two SMB2 NEGOTIATE requests on the same connection, one worker can free conn->preauth_info on the failing-negotiate path while a concurrent send-path worker is reading it, producing a slab use-after-free read (KASAN-confirmed). The send-path read tested conn->preauth_info for NULL but raced with the free that occurs between the NULL check and the dereference, so the NULL guard alone does not close the window. Serialize the NEGOTIATE-branch read in smb3_preauth_hash_rsp() under ksmbd_conn_lock(conn) and re-check conn->preauth_info inside the lock. Because the negotiate handler holds conn_lock across its kfree + NULL assi",
"evidence": "osv:CVE-2026-72422",
"products": [
{
"name": {
"value": "Kernel",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.15.212",
"evidence": "/affected/1/ranges"
},
{
"value": "6.1.178",
"evidence": "/affected/1/ranges"
},
{
"value": "6.6.145",
"evidence": "/affected/1/ranges"
},
{
"value": "6.12.97",
"evidence": "/affected/1/ranges"
},
{
"value": "6.18.40",
"evidence": "/affected/1/ranges"
},
{
"value": "7.1.5",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
}
],
"severity": "critical",
"structured": {
"id": "CVE-2026-72422",
"aliases": [
"CVE-2026-72422"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "dd4e4c811898410e6a3ae3b63207b7c542860907"
},
{
"fixed": "c7bef84740d1d57848c74f6f5b996606e43ea4fe"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "aa7253c2393f6dcd6a1468b0792f6da76edad917"
},
{
"fixed": "d0a469122e7bf8338fec1949fb1e8e1290ed8caa"
},
{
"fixed": "7470511d085af1c7a043a60e53d52b512d5a10b1"
},
{
"fixed": "16a1ecf39c217e3d164bd32ef2a4f650abc067fa"
},
{
"fixed": "77bb0bbfcc4e777ca653174689e5e363f8ee63d1"
},
{
"fixed": "1c89da3baa2b1f269178afa87dc30479b8535776"
},
{
"fixed": "0c054227479ed7e36ebccb3a558bc0ef698264f6"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.15.61"
},
{
"fixed": "5.15.212"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.18.18"
},
{
"fixed": "5.19"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.19.2"
},
{
"fixed": "5.20"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "8a8315a5960bd2b5ffc75f44fc089e57c3b17c44"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "ff20f1875889dbe4a67c9298e609d7c88cf6456d"
}
]
}
],
"versions": [
"v5.15.211",
"v5.15.210",
"v5.15.209",
"v5.15.208",
"v5.15.207",
"v5.15.206",
"v5.15.205",
"v5.15.204",
"v5.15.203",
"v5.15.202",
"v5.15.201",
"v5.15.200",
"v5.15.199",
"v5.15.198",
"v5.15.197",
"v5.15.196",
"v5.15.195",
"v5.15.194",
"v5.15.193",
"v5.15.192",
"v5.15.191",
"v5.15.190",
"v5.15.189",
"v5.15.188",
"v5.15.187",
"v5.15.186",
"v5.15.185",
"v5.15.184",
"v5.15.183",
"v5.15.182",
"v5.15.181",
"v5.15.180",
"v5.15.179",
"v5.15.178",
"v5.15.177",
"v5.15.176",
"v5.15.175",
"v5.15.174",
"v5.15.173",
"v5.15.172",
"v5.15.171",
"v5.15.170",
"v5.15.169",
"v5.15.168",
"v5.15.167",
"v5.15.166",
"v5.15.165",
"v5.15.164",
"v5.15.163",
"v5.15.162",
"v5.15.161",
"v5.15.160",
"v5.15.159",
"v5.15.158",
"v5.15.157",
"v5.15.156",
"v5.15.155",
"v5.15.154",
"v5.15.153",
"v5.15.152",
"v5.15.151",
"v5.15.150",
"v5.15.149",
"v5.15.148",
"v5.15.147",
"v5.15.146",
"v5.15.145",
"v5.15.144",
"v5.15.143",
"v5.15.142",
"v5.15.141",
"v5.15.140",
"v5.15.139",
"v5.15.138",
"v5.15.137",
"v5.15.136",
"v5.15.135",
"v5.15.134",
"v5.15.133",
"v5.15.132",
"v5.15.131",
"v5.15.130",
"v5.15.129",
"v5.15.128",
"v5.15.127",
"v5.15.126",
"v5.15.125",
"v5.15.124",
"v5.15.123",
"v5.15.122",
"v5.15.121",
"v5.15.120",
"v5.15.119",
"v5.15.118",
"v5.15.117",
"v5.15.116",
"v5.15.115",
"v5.15.114",
"v5.15.113",
"v5.15.112",
"v5.15.111",
"v5.15.110",
"v5.15.109",
"v5.15.108",
"v5.15.107",
"v5.15.106",
"v5.15.105",
"v5.15.104",
"v5.15.103",
"v5.15.102",
"v5.15.101",
"v5.15.100",
"v5.15.99",
"v5.15.98",
"v5.15.97",
"v5.15.96",
"v5.15.95",
"v5.15.94",
"v5.15.93",
"v5.15.92",
"v5.15.91",
"v5.15.90",
"v5.15.89",
"v5.15.88",
"v5.15.87",
"v5.15.86",
"v5.15.85",
"v5.15.84",
"v5.15.83",
"v5.15.82",
"v5.15.81",
"v5.15.80",
"v5.15.79",
"v5.15.78",
"v5.15.77",
"v5.15.76",
"v5.15.75",
"v5.15.74",
"v5.15.73",
"v5.15.72",
"v5.15.71",
"v5.15.70",
"v5.15.69",
"v5.15.68",
"v5.15.67",
"v5.15.66",
"v5.15.65",
"v5.15.64",
"v5.15.63",
"v5.15.62",
"v5.15.61",
"v5.18.19",
"v5.18.18",
"v5.19.17",
"v5.19.16",
"v5.19.15",
"v5.19.14",
"v5.19.13",
"v5.19.12",
"v5.19.11",
"v5.19.10",
"v5.19.9",
"v5.19.8",
"v5.19.7",
"v5.19.6",
"v5.19.5",
"v5.19.4",
"v5.19.3",
"v5.19.2"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72422.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.15.212"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.16.0"
},
{
"fixed": "6.1.178"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.0.0"
},
{
"fixed": "6.6.145"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.2.0"
},
{
"fixed": "6.12.97"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.7.0"
},
{
"fixed": "6.18.40"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.13.0"
},
{
"fixed": "7.1.5"
}
]
}
],
"package": {
"name": "Kernel",
"ecosystem": "Linux"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72422.json"
}
}
],
"modified": "2026-10-08T02:51:47.949631305Z",
"provider": "osv",
"references": [
"https://git.kernel.org/stable/c/0c054227479ed7e36ebccb3a558bc0ef698264f6",
"https://git.kernel.org/stable/c/16a1ecf39c217e3d164bd32ef2a4f650abc067fa",
"https://git.kernel.org/stable/c/1c89da3baa2b1f269178afa87dc30479b8535776",
"https://git.kernel.org/stable/c/7470511d085af1c7a043a60e53d52b512d5a10b1",
"https://git.kernel.org/stable/c/77bb0bbfcc4e777ca653174689e5e363f8ee63d1",
"https://git.kernel.org/stable/c/c7bef84740d1d57848c74f6f5b996606e43ea4fe",
"https://git.kernel.org/stable/c/d0a469122e7bf8338fec1949fb1e8e1290ed8caa",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72422.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-72422",
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
],
"provider_metadata": {
"cna_assigner": "Linux",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72422.json"
}
},
"related_cves": [
{
"value": "CVE-2026-72422",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 98348,
"published_at": "2026-08-15T05:56:41.09+00:00"
}