nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file() dentry_create() can hypothetically provide a different dentry than the one passed in. This could happen, for example, if the exported filesystem is NFS, and the server returned to OPEN a filehandle which matched a directory that was already in the dcache. Clearly this would not be expected! If this were to happen the dentry (child) that was already stored in resfhp could be freed and later dereferenced. We shouldn't call fh_compose() until we are certain that we have the final dentry, so this patch moved the fh_compose() call to two places: one for the case where the target already exists, and one after dentry_create() where it was created.
CVE-2026-89677
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-2026-89677
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": "64a989dbd144e0622371396461b11335459692d2",
"lessThan": "033e783709ce99662cf81f6abcad746a8da9d35f",
"versionType": "git"
},
{
"status": "affected",
"version": "64a989dbd144e0622371396461b11335459692d2",
"lessThan": "3e2c79360c6a89975ec5b5a7d4ef937e4db91a27",
"versionType": "git"
}
],
"programFiles": [
"fs/nfsd/nfs4proc.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.0",
"versionType": "semver"
},
{
"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/nfs4proc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89677
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #35166 · Revision 1
- Added to Heist Feed
- Publisher date