CVE-2026-97564 (GCVE-0-2026-97564)
Vulnerability from cvelistv5 – Published: 2026-09-25 10:21 – Updated: 2026-10-30 12:37
VLAI
EPSS
VEX
Title
smb: client: reject userspace cifs.idmap descriptions
Summary
In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject userspace cifs.idmap descriptions
cifs.idmap key descriptions carry authority-bearing fields (owner and
group SIDs and uid/gid values in "os:"/"gs:"/"oi:"/"gi:" form) that the
cifs.idmap upcall helper treats as kernel-originating inputs. Unlike
its sibling cifs.spnego, the cifs.idmap key type has no vet_description
hook, so userspace can create keys of this type through
request_key(2)/add_key(2) and supply those fields without CIFS origin.
A request_key(2) call with a non-NULL callout then drives a root
usermodehelper upcall (/sbin/request-key -> cifs.idmap) that consumes
the unvetted description in root context.
Only accept cifs.idmap descriptions while CIFS is using its private
root_cred to request the key. id_to_sid()/sid_to_id() already run
under override_creds(root_cred), so the kernel-originated path is
unaffected.
This mirrors commit 3da1fdf4efbc ("smb: client: reject userspace
cifs.spnego descriptions"), which applied the same restriction to
cifs.spnego.
Severity
No CVSS data available.
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < 91da70a2e5c6f54e1316d51e0e6911e78ef5e09a
(git)
Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < 856cb3f05b49d23dc1542f78696e20c4ea6dd7de (git) Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a (git) Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < 17c93bcd17755523c21abb22cbf2a41a6eb0caaf (git) Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < e5964064e3fbe6325893408faff08ca33de0e2c3 (git) Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < 96751028c0d4dec785709ea3eb0ab38a4f2ded96 (git) Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1 (git) Affected: 4d79dba0e00749fa40de8ef13a9b85ce57a1603b , < d9d7eeb0cea5b55b82888f443622fd8d4ee064f3 (git) |
guessed | |
| Linux | Linux |
Affected:
3.0
Unaffected: 0 , < 3.0 (semver) Unaffected: 5.10.273 , ≤ 5.10.* (semver) Unaffected: 5.15.224 , ≤ 5.15.* (semver) Unaffected: 6.1.189 , ≤ 6.1.* (semver) Unaffected: 6.6.158 , ≤ 6.6.* (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix) |
guessed |
{
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"programFiles": [
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"versions": [
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},
{
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"status": "unaffected",
"version": "0",
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},
{
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"status": "unaffected",
"version": "5.10.273",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.224",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.6.158",
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},
{
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"status": "unaffected",
"version": "6.12.111",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.273",
"versionStartIncluding": "3.0",
"vulnerable": true
},
{
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"versionStartIncluding": "3.0",
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},
{
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{
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{
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},
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},
{
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},
{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: reject userspace cifs.idmap descriptions\n\ncifs.idmap key descriptions carry authority-bearing fields (owner and\ngroup SIDs and uid/gid values in \"os:\"/\"gs:\"/\"oi:\"/\"gi:\" form) that the\ncifs.idmap upcall helper treats as kernel-originating inputs. Unlike\nits sibling cifs.spnego, the cifs.idmap key type has no vet_description\nhook, so userspace can create keys of this type through\nrequest_key(2)/add_key(2) and supply those fields without CIFS origin.\nA request_key(2) call with a non-NULL callout then drives a root\nusermodehelper upcall (/sbin/request-key -\u003e cifs.idmap) that consumes\nthe unvetted description in root context.\n\nOnly accept cifs.idmap descriptions while CIFS is using its private\nroot_cred to request the key. id_to_sid()/sid_to_id() already run\nunder override_creds(root_cred), so the kernel-originated path is\nunaffected.\n\nThis mirrors commit 3da1fdf4efbc (\"smb: client: reject userspace\ncifs.spnego descriptions\"), which applied the same restriction to\ncifs.spnego."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-30T12:37:26.400Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/91da70a2e5c6f54e1316d51e0e6911e78ef5e09a"
},
{
"url": "https://git.kernel.org/stable/c/856cb3f05b49d23dc1542f78696e20c4ea6dd7de"
},
{
"url": "https://git.kernel.org/stable/c/f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a"
},
{
"url": "https://git.kernel.org/stable/c/17c93bcd17755523c21abb22cbf2a41a6eb0caaf"
},
{
"url": "https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3"
},
{
"url": "https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96"
},
{
"url": "https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1"
},
{
"url": "https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3"
}
],
"title": "smb: client: reject userspace cifs.idmap descriptions",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-97564",
"datePublished": "2026-09-25T10:21:51.858Z",
"dateReserved": "2026-09-24T16:01:01.155Z",
"dateUpdated": "2026-10-30T12:37:26.400Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-97564",
"date": "2026-11-01",
"epss": "0.00216",
"percentile": "0.12102"
},
"microsoft_vex": {
"current_release_date": "2026-10-21T18:38:30.000Z",
"cve": "CVE-2026-97564",
"id": "msrc_CVE-2026-97564",
"initial_release_date": "2026-09-28T01:57:43.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"product_status:under_investigation": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "smb: client: reject userspace cifs.idmap descriptions",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-97564.json",
"version": "4"
},
"nvd": {
"cve": {
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"product": "Linux",
"programFiles": [
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"vendor": "Linux",
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"versionType": "git"
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{
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{
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]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.0"
},
{
"lessThan": "3.0",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.273",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "5.15.224",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: reject userspace cifs.idmap descriptions\n\ncifs.idmap key descriptions carry authority-bearing fields (owner and\ngroup SIDs and uid/gid values in \"os:\"/\"gs:\"/\"oi:\"/\"gi:\" form) that the\ncifs.idmap upcall helper treats as kernel-originating inputs. Unlike\nits sibling cifs.spnego, the cifs.idmap key type has no vet_description\nhook, so userspace can create keys of this type through\nrequest_key(2)/add_key(2) and supply those fields without CIFS origin.\nA request_key(2) call with a non-NULL callout then drives a root\nusermodehelper upcall (/sbin/request-key -\u003e cifs.idmap) that consumes\nthe unvetted description in root context.\n\nOnly accept cifs.idmap descriptions while CIFS is using its private\nroot_cred to request the key. id_to_sid()/sid_to_id() already run\nunder override_creds(root_cred), so the kernel-originated path is\nunaffected.\n\nThis mirrors commit 3da1fdf4efbc (\"smb: client: reject userspace\ncifs.spnego descriptions\"), which applied the same restriction to\ncifs.spnego."
}
],
"id": "CVE-2026-97564",
"lastModified": "2026-10-30T13:21:08.353",
"metrics": {},
"published": "2026-09-25T11:17:07.007",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/17c93bcd17755523c21abb22cbf2a41a6eb0caaf"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1"
},
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"url": "https://git.kernel.org/stable/c/856cb3f05b49d23dc1542f78696e20c4ea6dd7de"
},
{
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"url": "https://git.kernel.org/stable/c/91da70a2e5c6f54e1316d51e0e6911e78ef5e09a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96"
},
{
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"url": "https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-10-30T06:31:21+00:00",
"cve": "CVE-2026-97564",
"id": "CVE-2026-97564",
"initial_release_date": "2026-09-25T00:00:00+00:00",
"product_status:known_affected": "237",
"product_status:known_not_affected": "42",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: smb: client: reject userspace cifs.idmap descriptions",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97564.json",
"version": "3"
}
}
}
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