nfsd: Reset write verifier when async COPY writeback fails
In the Linux kernel, the following vulnerability has been resolved: nfsd: Reset write verifier when async COPY writeback fails Async COPY captures nn->writeverf at request time and reports it to the client via CB_OFFLOAD after the worker kthread completes. When the post-copy vfs_fsync_range() or filemap_check_wb_err() in _nfsd_copy_file_range() reports an error, the worker correctly leaves NFSD4_COPY_F_COMMITTED clear so that CB_OFFLOAD encodes wr_stable_how as NFS_UNSTABLE, but the server's write verifier is not rotated. A client that receives NFS_UNSTABLE in CB_OFFLOAD follows up with COMMIT to make the copied data durable. With the verifier unchanged, COMMIT returns the same value the client just received via CB_OFFLOAD, and the client concludes the copy is durable -- silently dropping the data whose writeback in fact failed. This violates the UNSTABLE+COMMIT durability contract (RFC 7862 section 15.1, RFC 8881 section 18.32) and matches the bug just fixed in nfsd_vfs_write() and nfsd_commit(). Rotate nn->writeverf at the writeback-failure site. The async COPY worker has no svc_rqst, so commit_reset_write_verifier() is not available here; calling nfsd_reset_write_verifier() directly mirrors the trace-less reset already used by nfsd_file_check_write_error() for the same purpose. Filter out -EAGAIN and -ESTALE, matching commit_reset_write_verifier(), since neither indicates a durable-storage failure.
CVE-2026-89706
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-2026-89706
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": "817c6eb975798647c4bbbfc9eb288aa413ec7f65",
"lessThan": "cc5f7cef0659a27c13dd33edd8e2f79257b095c6",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "c6d2f6372c7e0f76b9c148ff7696aec64da0b5b7",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "8a08ffe73eb2aa6bc6f88763da7e2b55bab6493a",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "6b13d26cc21b6320a3c61d5e4cee2ce9a589b181",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "31d4d0a62ec4bafbcdbad142f11ab1f90794b1d0",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "591134e059e3456180244a826d6917cdc183140b",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "bf0cd31a9abcb728c17d79b4c2cc533612a8b6af",
"versionType": "git"
},
{
"status": "affected",
"version": "eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d",
"lessThan": "f5cb2276954cb80987a93ef9f9dfbfdbfc0f10b9",
"versionType": "git"
},
{
"status": "affected",
"version": "5.10.220",
"lessThan": "5.10.270",
"versionType": "semver"
}
],
"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": "5.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.14",
"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/nfs4proc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89706
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #35189 · Revision 1
- Added to Heist Feed
- Publisher date