{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89675", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.747Z", "datePublished": "2026-09-11T19:45:59.635Z", "dateUpdated": "2026-09-11T19:45:59.635Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-11T19:45:59.635Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix UAF in async copy cancel and shutdown\n\nAn async copy could be freed or used after free while a teardown caller\n(OFFLOAD_CANCEL, nfsd4_shutdown_copy, nfsd4_cancel_copy_by_sb) raced the\ncopy kthread:\n\n - find_async_copy() bumped copy->refcount but left the copy on\n clp->async_copies, so the reaper's cleanup_async_copy() could run\n release_copy_files() concurrently with a cancel/shutdown caller. Both\n put and NULL nf_src/nf_dst without a common lock, double-putting the\n nfsd_file and freeing it early.\n\n - nfsd4_do_async_copy() set NFSD4_COPY_F_STOPPED before its final uses\n of the copy (nfsd_update_cmtime_attr() on copy->nf_dst,\n nfsd4_send_cb_offload()). nfsd4_stop_copy() treats a set STOPPED bit\n as \"kthread done, skip kthread_stop()\", so a teardown caller ran\n release_copy_files() -- which puts and NULLs nf_dst -- while the\n kthread still dereferenced it (NULL/UAF).\n\n - copy->copy_task was never pinned. The one-shot kthread self-reaps on\n return, so kthread_stop()'s get_task_struct() could touch a freed\n task_struct.\n\n - co_cb is embedded in the copy, but nfsd4_send_cb_offload() held a\n reference only on the client, so a concurrent teardown could free\n the copy while the CB_OFFLOAD callback was in flight.\n\nFix the teardown lifetime as a whole:\n\n - find_async_copy() unlinks the copy (clear cp_clp, list_del_init)\n under async_lock; the cancel, shutdown, and sb-cancel paths drop the\n list-membership reference via nfs4_put_copy() after nfsd4_stop_copy().\n Drop the now-redundant list_del fixup from cleanup_async_copy().\n\n - Because unlinking hides the copy from the reaper, its\n cleanup_async_copy() can no longer remove the copy's s2s_cp_stateids\n entry; the cancel/shutdown/sb-cancel paths now call\n nfs4_free_copy_state() themselves (while cp_clp is still valid) so\n the entry does not dangle at freed memory for the laundromat and\n manage_cpntf_state() to dereference.\n\n - Give the kthread its own reference, taken in nfsd4_copy() before\n wake_up_process() and dropped at the end of nfsd4_do_async_copy();\n call wake_up_process() before list_add().\n\n - Pin the task_struct with get_task_struct() in nfsd4_copy(), released\n in nfs4_put_copy(), so kthread_stop() is safe whenever the kthread\n exits. Set NFSD4_COPY_F_STOPPED only in nfsd4_stop_copy(), which now\n always kthread_stop()s before release_copy_files(); completion is\n still reported via NFSD4_COPY_F_COMPLETED, so\n nfsd4_has_active_async_copies() is unaffected. Each teardown caller\n removes the copy from clp->async_copies first, so kthread_stop() runs\n exactly once.\n\n - Take a copy reference in nfsd4_send_cb_offload(), dropped in\n nfsd4_cb_offload_release(). The kthread still holds its own reference\n there, so the refcount_inc() cannot race the final free.\n\n - Read cp_clp with smp_load_acquire() to pair with the unordered\n set_bit()/clear_bit() writers (Documentation/atomic_bitops.rst)."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfs4proc.c"], "versions": [{"version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3", "lessThan": "9031493ef7369d5c59c4bacc96f0c85965f09a98", "status": "affected", "versionType": "git"}, {"version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3", "lessThan": "a385cf5e016b748babf94cc664e43a26e17db117", "status": "affected", "versionType": "git"}, {"version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3", "lessThan": "62c0f6eaf050bb9284c1f9cac6ed1770092e6b95", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/nfs4proc.c"], "versions": [{"version": "4.20", "status": "affected"}, {"version": "0", "lessThan": "4.20", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3-rc1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.18.51"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "7.3-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/9031493ef7369d5c59c4bacc96f0c85965f09a98"}, {"url": "https://git.kernel.org/stable/c/a385cf5e016b748babf94cc664e43a26e17db117"}, {"url": "https://git.kernel.org/stable/c/62c0f6eaf050bb9284c1f9cac6ed1770092e6b95"}], "title": "nfsd: fix UAF in async copy cancel and shutdown", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4proc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "9031493ef7369d5c59c4bacc96f0c85965f09a98", "status": "affected", "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3", "versionType": "git"}, {"lessThan": "a385cf5e016b748babf94cc664e43a26e17db117", "status": "affected", "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3", "versionType": "git"}, {"lessThan": "62c0f6eaf050bb9284c1f9cac6ed1770092e6b95", "status": "affected", "version": "e0639dc5805a9d4faaa2c07ad98fa853b9529dd3", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/nfs4proc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.20"}, {"lessThan": "4.20", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.51", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix UAF in async copy cancel and shutdown\n\nAn async copy could be freed or used after free while a teardown caller\n(OFFLOAD_CANCEL, nfsd4_shutdown_copy, nfsd4_cancel_copy_by_sb) raced the\ncopy kthread:\n\n - find_async_copy() bumped copy->refcount but left the copy on\n clp->async_copies, so the reaper's cleanup_async_copy() could run\n release_copy_files() concurrently with a cancel/shutdown caller. Both\n put and NULL nf_src/nf_dst without a common lock, double-putting the\n nfsd_file and freeing it early.\n\n - nfsd4_do_async_copy() set NFSD4_COPY_F_STOPPED before its final uses\n of the copy (nfsd_update_cmtime_attr() on copy->nf_dst,\n nfsd4_send_cb_offload()). nfsd4_stop_copy() treats a set STOPPED bit\n as \"kthread done, skip kthread_stop()\", so a teardown caller ran\n release_copy_files() -- which puts and NULLs nf_dst -- while the\n kthread still dereferenced it (NULL/UAF).\n\n - copy->copy_task was never pinned. The one-shot kthread self-reaps on\n return, so kthread_stop()'s get_task_struct() could touch a freed\n task_struct.\n\n - co_cb is embedded in the copy, but nfsd4_send_cb_offload() held a\n reference only on the client, so a concurrent teardown could free\n the copy while the CB_OFFLOAD callback was in flight.\n\nFix the teardown lifetime as a whole:\n\n - find_async_copy() unlinks the copy (clear cp_clp, list_del_init)\n under async_lock; the cancel, shutdown, and sb-cancel paths drop the\n list-membership reference via nfs4_put_copy() after nfsd4_stop_copy().\n Drop the now-redundant list_del fixup from cleanup_async_copy().\n\n - Because unlinking hides the copy from the reaper, its\n cleanup_async_copy() can no longer remove the copy's s2s_cp_stateids\n entry; the cancel/shutdown/sb-cancel paths now call\n nfs4_free_copy_state() themselves (while cp_clp is still valid) so\n the entry does not dangle at freed memory for the laundromat and\n manage_cpntf_state() to dereference.\n\n - Give the kthread its own reference, taken in nfsd4_copy() before\n wake_up_process() and dropped at the end of nfsd4_do_async_copy();\n call wake_up_process() before list_add().\n\n - Pin the task_struct with get_task_struct() in nfsd4_copy(), released\n in nfs4_put_copy(), so kthread_stop() is safe whenever the kthread\n exits. Set NFSD4_COPY_F_STOPPED only in nfsd4_stop_copy(), which now\n always kthread_stop()s before release_copy_files(); completion is\n still reported via NFSD4_COPY_F_COMPLETED, so\n nfsd4_has_active_async_copies() is unaffected. Each teardown caller\n removes the copy from clp->async_copies first, so kthread_stop() runs\n exactly once.\n\n - Take a copy reference in nfsd4_send_cb_offload(), dropped in\n nfsd4_cb_offload_release(). The kthread still holds its own reference\n there, so the refcount_inc() cannot race the final free.\n\n - Read cp_clp with smp_load_acquire() to pair with the unordered\n set_bit()/clear_bit() writers (Documentation/atomic_bitops.rst)."}], "id": "CVE-2026-89675", "lastModified": "2026-09-11T20:19:54.143", "metrics": {}, "published": "2026-09-11T20:19:54.143", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/62c0f6eaf050bb9284c1f9cac6ed1770092e6b95"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9031493ef7369d5c59c4bacc96f0c85965f09a98"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a385cf5e016b748babf94cc664e43a26e17db117"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: nfsd: Linux kernel (nfsd): Use-After-Free vulnerability in asynchronous copy handling", "id": "2532272", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532272"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.4", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in the Linux kernel's nfsd component. A race condition exists during asynchronous copy cancellation and shutdown operations, which can lead to a Use-After-Free (UAF) vulnerability. This allows an async copy object to be freed or used after being freed, potentially causing memory corruption and system instability. This issue arises when a teardown caller races with the copy kernel thread, leading to incorrect memory management."], "name": "CVE-2026-89675", "public_date": "2026-09-11T19:45:59Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89675\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89675\nhttps://git.kernel.org/stable/c/62c0f6eaf050bb9284c1f9cac6ed1770092e6b95\nhttps://git.kernel.org/stable/c/9031493ef7369d5c59c4bacc96f0c85965f09a98\nhttps://git.kernel.org/stable/c/a385cf5e016b748babf94cc664e43a26e17db117"], "threat_severity": "Important"}

{}