{"id":"CVE-2026-89706","revision":"f85f2feaaaaa48868eb3c63a393ab9d0","records":[{"revision":"f85f2feaaaaa48868eb3c63a393ab9d0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89706","aliases":[],"title":"nfsd: Reset write verifier when async COPY writeback fails","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: Reset write verifier when async COPY writeback fails\n\nAsync COPY captures nn->writeverf at request time and reports it to\nthe client via CB_OFFLOAD after the worker kthread completes. When\nthe post-copy vfs_fsync_range() or filemap_check_wb_err() in\n_nfsd_copy_file_range() reports an error, the worker correctly\nleaves NFSD4_COPY_F_COMMITTED clear so that CB_OFFLOAD encodes\nwr_stable_how as NFS_UNSTABLE, but the server's write verifier is\nnot rotated.\n\nA client that receives NFS_UNSTABLE in CB_OFFLOAD follows up with\nCOMMIT to make the copied data durable. With the verifier\nunchanged, COMMIT returns the same value the client just received\nvia CB_OFFLOAD, and the client concludes the copy is durable --\nsilently dropping the data whose writeback in fact failed. This\nviolates the UNSTABLE+COMMIT durability contract (RFC 7862 section\n15.1, RFC 8881 section 18.32) and matches the bug just fixed in\nnfsd_vfs_write() and nfsd_commit().\n\nRotate nn->writeverf at the writeback-failure site. The async COPY\nworker has no svc_rqst, so commit_reset_write_verifier() is not\navailable here; calling nfsd_reset_write_verifier() directly\nmirrors the trace-less reset already used by\nnfsd_file_check_write_error() for the same purpose. Filter out\n-EAGAIN and -ESTALE, matching commit_reset_write_verifier(), since\nneither indicates a durable-storage failure.","state":0,"publishedAt":"2026-09-11T19:46:22.561+00:00","modifiedAt":"2026-10-19T08:51:19.292+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs4proc.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"817c6eb975798647c4bbbfc9eb288aa413ec7f65\",\n                            \"lessThan\": \"cc5f7cef0659a27c13dd33edd8e2f79257b095c6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"c6d2f6372c7e0f76b9c148ff7696aec64da0b5b7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"8a08ffe73eb2aa6bc6f88763da7e2b55bab6493a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"6b13d26cc21b6320a3c61d5e4cee2ce9a589b181\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"31d4d0a62ec4bafbcdbad142f11ab1f90794b1d0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"591134e059e3456180244a826d6917cdc183140b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"bf0cd31a9abcb728c17d79b4c2cc533612a8b6af\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"eac0b17a77fbd763d305a5eaa4fd1119e5a0fe0d\",\n                            \"lessThan\": \"f5cb2276954cb80987a93ef9f9dfbfdbfc0f10b9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.10.220\",\n                            \"lessThan\": \"5.10.270\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/nfsd/nfs4proc.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/cc5f7cef0659a27c13dd33edd8e2f79257b095c6","https://git.kernel.org/stable/c/c6d2f6372c7e0f76b9c148ff7696aec64da0b5b7","https://git.kernel.org/stable/c/8a08ffe73eb2aa6bc6f88763da7e2b55bab6493a","https://git.kernel.org/stable/c/6b13d26cc21b6320a3c61d5e4cee2ce9a589b181","https://git.kernel.org/stable/c/31d4d0a62ec4bafbcdbad142f11ab1f90794b1d0","https://git.kernel.org/stable/c/591134e059e3456180244a826d6917cdc183140b","https://git.kernel.org/stable/c/bf0cd31a9abcb728c17d79b4c2cc533612a8b6af","https://git.kernel.org/stable/c/f5cb2276954cb80987a93ef9f9dfbfdbfc0f10b9"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89706","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89706","identifiers":["CVE-2026-89706"]},"retained":false,"historicalAffected":[]}],"coverage":[]}