smb: client: harden POSIX SID length parsing
In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.
CVE-2026-64380
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64380
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "171605aed68380c2fa75dff9b3a1ed427c50065b",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "4213c1208978483021d7d125c131de3985d38f61",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "96e889bc1e759c83f25093e8c2f3da31b4973f30",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "0de5b8e76847f5de26f364a82c6602c4881c30da",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "427eb7eb46425fec845a43e861f3d6e2899cae59",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "86c5d470f5d42e61123b2f4b4f0b91f4eee5b980",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "46a84715a015cb48e1b9c219dc88c03d8a541ea4",
"versionType": "git"
},
{
"status": "affected",
"version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
"lessThan": "7ad2bcf2441430bb2e918fb3ef9a90d775a6e422",
"versionType": "git"
}
],
"programFiles": [
"fs/smb/client/smb2pdu.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/smb/client/smb2pdu.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64380
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #41021 · Revision 1
- Added to Heist Feed
- Publisher date