GHSA-2C6M-5VJC-XQC6
Vulnerability from github – Published: 2026-10-06 09:31 – Updated: 2026-10-07 09:32In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix potential OOB read in smb3_enum_snapshots()
If snapshot_array_size is smaller than GMT_TOKEN_SIZE, smb3_enum_snapshots() sets ret_data_len to sizeof(struct smb_snapshot_array) without verifying the actual length of the server's reply.
Because SMB2_ioctl() places no lower bound on the server-supplied OutputCount and allocates retbuf to exactly that length, a short reply results in ret_data_len exceeding the size of retbuf. The subsequent copy_to_user() then reads past the end of retbuf, leaking adjacent slab memory to userspace. The subsequent clamp check is ineffective as it only reduces ret_data_len.
Fix this by rejecting replies shorter than sizeof(struct smb_snapshot_array) with -EIO. Note that the bound is set to the 12-byte struct size rather than the 16-byte MIN_SNAPSHOT_ARRAY_SIZE defined in MS-SMB2 3.3.5.15.1, because 12 bytes is exactly what copy_to_user() attempts to read.
{
"affected": [],
"aliases": [
"CVE-2026-98169"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-06T09:17:58Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix potential OOB read in smb3_enum_snapshots()\n\nIf snapshot_array_size is smaller than GMT_TOKEN_SIZE,\nsmb3_enum_snapshots() sets ret_data_len to\nsizeof(struct smb_snapshot_array) without verifying the actual length\nof the server\u0027s reply.\n\nBecause SMB2_ioctl() places no lower bound on the server-supplied\nOutputCount and allocates retbuf to exactly that length, a short reply\nresults in ret_data_len exceeding the size of retbuf. The subsequent\ncopy_to_user() then reads past the end of retbuf, leaking adjacent slab\nmemory to userspace. The subsequent clamp check is ineffective as it\nonly reduces ret_data_len.\n\nFix this by rejecting replies shorter than\nsizeof(struct smb_snapshot_array) with -EIO. Note that the bound is set\nto the 12-byte struct size rather than the 16-byte\nMIN_SNAPSHOT_ARRAY_SIZE defined in MS-SMB2 3.3.5.15.1, because 12 bytes\nis exactly what copy_to_user() attempts to read.",
"id": "GHSA-2c6m-5vjc-xqc6",
"modified": "2026-10-07T09:32:12Z",
"published": "2026-10-06T09:31:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98169"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/15a221c734b9d044ab769e7e3606b2cab96fb65a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1cdf0d304d820fb13bf0faf532c3459600f9ea43"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/210f0f1f67817e7d2348b86b5115a9b85ef5c98b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4775c3b7a597907e0b97556c7986fda238a377ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/74995ee8305a7c4d76ee70d6acd996a75eda3c03"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dbe452a905dfe2804647530a9ff3d7e3826ed04d"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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