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vuln-cve/data/2026/97xxx/CVE-2026-97562.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-97562",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-09-24T16:01:01.155Z",
"datePublished": "2026-09-25T10:21:50.664Z",
"dateUpdated": "2026-10-19T09:09:25.220Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-10-19T09:09:25.220Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: pin DFS superblock in iterator callback\n\ntcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()\ntakes its active reference only after iterate_supers_type() has dropped\ns_umount and its passive reference. Concurrent DFS automount expiry can\ntherefore free the superblock before cifs_sb_active() uses it.\n\nA deterministic KASAN test reproduces the race as:\n\n BUG: KASAN: slab-use-after-free in cifs_sb_active+0x77/0x80\n\nThe same test passes with this change applied.\n\nTake the active reference in the callback while iterate_supers_type()\nstill holds s_umount shared. cifs_put_tcp_super() remains the matching\nrelease."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
"baseScore": 7.5,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The racing side is started by the remote SMB server: dropping the session or replying STATUS_NETWORK_NAME_DELETED makes the client run smb2_reconnect() -> cifs_tree_connect() -> cifs_get_dfs_tcon_super() -> __cifs_get_super(). There, tcon_super_cb() saves a raw superblock pointer that is used after s_umount is released.\nAC:H - The server can force reconnects repeatedly, but the superblock is only freed if a DFS-link automount expires via cifs_expire_automounts() (a 500s periodic timer, idle submount only) inside the small gap between iterate_supers_type() returning and cifs_sb_active(). The attacker does not control that timing.\nPR:N - The attacker is the SMB/DFS server or a network peer that can reset the client's session. Forcing the client's tree reconnect needs no account or privilege on the client.\nUI:R - A victim must have mounted a DFS share with an automounted DFS link from the attacker-reachable server (cifs mounts need real CAP_SYS_ADMIN, not a user namespace), and the link must be idle long enough to expire.\nS:U - The use-after-free corrupts memory in the same kernel that runs the CIFS client, so no separate security authority is crossed.\nC:H - After the freed super_block and cifs_sb_info are reused, the reconnect path keeps reading them (cifs_sb_active() on freed memory, then CIFS_SB(sb) fields in tree_connect_dfs_target()), so reclaimed slab contents can be read.\nI:H - cifs_sb_active() increments counters in the freed cifs_sb/sb, and cifs_update_super_prepath() frees and replaces cifs_sb->prepath in the freed cifs_sb_info. Both are writes into freed memory that can be turned into heap corruption.\nA:H - The fix commit reports a KASAN slab-use-after-free in cifs_sb_active(); without KASAN the corrupted superblock refcounts and the later cifs_put_tcp_super()/deactivate_super() can crash the kernel."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/smb/client/misc.c"
],
"versions": [
{
"version": "bacd704a95ad0b93af995aae4a523aa046f46563",
"lessThan": "3c9acc9835c304013a4faeb969fe9333d66ca9f8",
"status": "affected",
"versionType": "git"
},
{
"version": "bacd704a95ad0b93af995aae4a523aa046f46563",
"lessThan": "ea43a15cea36dc5ddd832be5bddeac7dd804cbcf",
"status": "affected",
"versionType": "git"
},
{
"version": "bacd704a95ad0b93af995aae4a523aa046f46563",
"lessThan": "a6b6561522212af852c9ad8a7dca8d59ef2c7377",
"status": "affected",
"versionType": "git"
},
{
"version": "bacd704a95ad0b93af995aae4a523aa046f46563",
"lessThan": "5b01a8c0209690db75341528ec53fd87e0ac1460",
"status": "affected",
"versionType": "git"
},
{
"version": "bacd704a95ad0b93af995aae4a523aa046f46563",
"lessThan": "d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/smb/client/misc.c"
],
"versions": [
{
"version": "5.7",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.7",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.6.158",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.111",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.53",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.2.7",
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.7",
"versionEndExcluding": "6.6.158"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.7",
"versionEndExcluding": "6.12.111"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.7",
"versionEndExcluding": "6.18.53"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.7",
"versionEndExcluding": "7.2.7"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.7",
"versionEndExcluding": "7.3"
}
]
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]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/3c9acc9835c304013a4faeb969fe9333d66ca9f8"
},
{
"url": "https://git.kernel.org/stable/c/ea43a15cea36dc5ddd832be5bddeac7dd804cbcf"
},
{
"url": "https://git.kernel.org/stable/c/a6b6561522212af852c9ad8a7dca8d59ef2c7377"
},
{
"url": "https://git.kernel.org/stable/c/5b01a8c0209690db75341528ec53fd87e0ac1460"
},
{
"url": "https://git.kernel.org/stable/c/d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818"
}
],
"title": "smb: client: pin DFS superblock in iterator callback",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
}
}