CVE-2026-99111 (GCVE-0-2026-99111)
Vulnerability from cvelistv5
Published
2026-10-28 10:34
Modified
2026-10-28 10:34
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix data corruption with concurrent writes and O_TRUNC
cifs_do_truncate() flushes dirty pages with filemap_write_and_wait()
and truncates the file on the server, but in the old code both
operations ran without holding i_rwsem or invalidate_lock. A
concurrent buffered write via netfs_perform_write() -- which only
needs i_rwsem shared -- could dirty new pages after the flush but
before the local truncation, and those pages would be silently
discarded by cifs_setsize() -> truncate_pagecache().
Fix by acquiring inode_lock (exclusive i_rwsem) and
filemap_invalidate_lock at the top of cifs_do_truncate(), so the
entire flush-truncate-resize sequence is atomic with respect to:
- buffered writes (blocked by exclusive i_rwsem, since
netfs_start_io_write takes i_rwsem shared),
- read page faults (blocked by exclusive invalidate_lock, since
filemap_fault takes it shared),
- writeback collection (blocked by netfs_wb_begin/netfs_wb_end
around the server truncate and local resize, since
netfs_writepages also acquires the wb lock).
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/client/file.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "4d143608a0445443a85c9b29f4c9f8e63d5dbfc9",
"status": "affected",
"version": "110fee6b9bb58a5c50047fc2594d415f741b591e",
"versionType": "git"
},
{
"lessThan": "ffa66fdc7d35b890606767c4d2c7ac26b4d90a99",
"status": "affected",
"version": "110fee6b9bb58a5c50047fc2594d415f741b591e",
"versionType": "git"
},
{
"lessThan": "a8603b52b39f520ea8a34def74c23fba87396d3e",
"status": "affected",
"version": "110fee6b9bb58a5c50047fc2594d415f741b591e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/smb/client/file.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"lessThan": "6.18",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.59",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.13",
"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": "6.18.59",
"versionStartIncluding": "6.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.13",
"versionStartIncluding": "6.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "6.18",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix data corruption with concurrent writes and O_TRUNC\n\ncifs_do_truncate() flushes dirty pages with filemap_write_and_wait()\nand truncates the file on the server, but in the old code both\noperations ran without holding i_rwsem or invalidate_lock. A\nconcurrent buffered write via netfs_perform_write() -- which only\nneeds i_rwsem shared -- could dirty new pages after the flush but\nbefore the local truncation, and those pages would be silently\ndiscarded by cifs_setsize() -\u003e truncate_pagecache().\n\nFix by acquiring inode_lock (exclusive i_rwsem) and\nfilemap_invalidate_lock at the top of cifs_do_truncate(), so the\nentire flush-truncate-resize sequence is atomic with respect to:\n\n - buffered writes (blocked by exclusive i_rwsem, since\n netfs_start_io_write takes i_rwsem shared),\n - read page faults (blocked by exclusive invalidate_lock, since\n filemap_fault takes it shared),\n - writeback collection (blocked by netfs_wb_begin/netfs_wb_end\n around the server truncate and local resize, since\n netfs_writepages also acquires the wb lock)."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-28T10:34:29.053Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/4d143608a0445443a85c9b29f4c9f8e63d5dbfc9"
},
{
"url": "https://git.kernel.org/stable/c/ffa66fdc7d35b890606767c4d2c7ac26b4d90a99"
},
{
"url": "https://git.kernel.org/stable/c/a8603b52b39f520ea8a34def74c23fba87396d3e"
}
],
"title": "smb: client: fix data corruption with concurrent writes and O_TRUNC",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-99111",
"datePublished": "2026-10-28T10:34:29.053Z",
"dateReserved": "2026-09-25T10:25:14.392Z",
"dateUpdated": "2026-10-28T10:34:29.053Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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