NFSv4/flexfiles: reject zero filehandle version count
In the Linux kernel, the following vulnerability has been resolved: NFSv4/flexfiles: reject zero filehandle version count ff_layout_alloc_lseg() decodes the filehandle-version array count from the flexfiles layout body. The value is used as the count for kzalloc_objs(), and the current code only rejects NULL. A zero count yields ZERO_SIZE_PTR, which can be stored in dss_info->fh_versions even though later flexfiles paths assume that at least one filehandle version exists. Reject fh_count == 0 before the allocation, matching the existing zero version_count validation in the flexfiles GETDEVICEINFO parser. A QEMU/KASAN run with a malformed flexfiles layout hit: KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:ff_layout_encode_ff_layoutupdate.isra.0+0x15f/0x750 ff_layout_encode_layoutreturn+0x683/0x970 nfs4_xdr_enc_layoutreturn+0x278/0x3a0 Kernel panic - not syncing: Fatal exception The patched kernel rejects the malformed layout without KASAN/oops/panic, and a valid fh_count=1 regression still opens, reads, and unmounts cleanly.
CVE-2026-53392
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-2026-53392
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": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "9033591535c066726f5b505126ccb4068b98fa4f",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "18cc6d57a14fa65ab2a2b52279f549041c4bc9cf",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "be7829715e341b42846437dd9e721005db59f0cc",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "eeabb9020721db6bc132e68eeae380b8d4fb4b04",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "7779c85028a0676fb190cde4f0c540f4f8e97761",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "d8c90c7cc061265d5f2813a1f5c82ef2f4707e67",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "2131ed64b767ffa8bcdb3677d90f3964e39aabc8",
"versionType": "git"
},
{
"status": "affected",
"version": "d67ae825a59d639e4d8b82413af84d854617a87e",
"lessThan": "2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2",
"versionType": "git"
}
],
"programFiles": [
"fs/nfs/flexfilelayout/flexfilelayout.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.0",
"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": "6.18.38",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfs/flexfilelayout/flexfilelayout.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-53392
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40821 · Revision 1
- Added to Heist Feed
- Publisher date