NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check
In the Linux kernel, the following vulnerability has been resolved: NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check The header for commit e75b23f9e323 ("nfsd: check d_can_lookup in fh_verify of directories") details the assumption that justified adding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is invalid (in the case of NFS reexport). When NFSD exports an NFS filesystem it is very possible for nfsd_mode_check() to encounter a @dentry that doesn't have i_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and NFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()). So remove nfsd_mode_check()'s WARN_ON_ONCE(). The nfserr_notdir return on that branch must stay. It guards the subsequent lookup_one_unlocked() -> __lookup_slow() path, which calls inode->i_op->lookup() with no NULL check, so returning nfserr_notdir is what keeps a client LOOKUP into such a @dentry from dereferencing a NULL method pointer.
CVE-2026-89711
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-2026-89711
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": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "ae251937c6f0237e5b555a5e4ba4595b8206e865",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "e145e8d67a5d41c72d322e7f87ab474d39d9dfb7",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "9f4434893a2783f7384d993cea883aff3fb7a52d",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "2ef131323999539038e306773c8256403834361b",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "b55b4d880bb080fa10eb08ba21a5d8679b8102fe",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "7ef182a8fe9c12b0d936880b1e504840639aa009",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "a275de3bac5635514ca830f2e46b5ff0e66b5c4c",
"versionType": "git"
},
{
"status": "affected",
"version": "e75b23f9e323b1e0759619c39d5a9f7a3a5d9d2c",
"lessThan": "aa0cf48a448c5a9fe1a1e880899ecd589ce39e6e",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/nfsfh.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/nfsd/nfsfh.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89711
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #35192 · Revision 1
- Added to Heist Feed
- Publisher date