{"id":"CVE-2026-89712","revision":"4eace85f6eee40a3b499b62158eebe61","records":[{"revision":"4eace85f6eee40a3b499b62158eebe61","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89712","aliases":[],"title":"NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock\n\nnfsd4_ssc_expire_umount() walks nn->nfsd_ssc_mount_list with\nlist_for_each_entry_safe(ni, tmp, ...).  For each expired entry it\nsets nsui_busy = true, drops nfsd_ssc_lock to run mntput() on the\nsource vfsmount, then reacquires the lock to list_del + kfree the\nentry and continue iterating via the macro's saved tmp pointer.\n\nThe nsui_busy flag protects the current ni from concurrent\nnfsd4_ssc_setup_dul() finders during the lock-drop window, but it\ndoes not pin tmp.  Another nfsd RPC thread that fails its source-\nserver mount and reaches nfsd4_ssc_cancel_dul() will, during that\nsame window, take nfsd_ssc_lock, list_del + kfree its own ssc_umount\nitem, and release the lock.  If that item is the saved tmp of the\nexpire walk, the next iteration dereferences a freed\nnfsd4_ssc_umount_item.\n\nRestart the walk from the head after the mntput() unlock window so\nno saved next pointer survives the lock-drop.  The list is bounded\nby the number of active inter-server source mounts (typically small)\nand the expire delayed-work runs periodically rather than per-IO,\nso the restart is cheap.","state":0,"publishedAt":"2026-09-11T19:46:27.018+00:00","modifiedAt":"2026-10-19T08:51:25.202+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/nfs4state.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"a4bc287943f5695209ff36bdc89f17b48d68fae7\",\n                            \"lessThan\": \"2b59029b8f24a99b5d844af2da3950d39d36eeea\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"d9e151fea5ed706c1284adacabd869b0be745db2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"659ee3da073164e1e6e40dfcbc26eeed85845f93\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"60680ae7243b22de3d09be990d8e23bcfc4af837\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"77de363d9a1c8cd35f20482782c612cda085791a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f4e44b393389c77958f7c58bf4415032b4cda15b\",\n                            \"lessThan\": \"036c1b182f4da65363e79ec0ac276edc6b7296e5\",\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/nfs4state.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:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/2b59029b8f24a99b5d844af2da3950d39d36eeea","https://git.kernel.org/stable/c/d9e151fea5ed706c1284adacabd869b0be745db2","https://git.kernel.org/stable/c/659ee3da073164e1e6e40dfcbc26eeed85845f93","https://git.kernel.org/stable/c/60680ae7243b22de3d09be990d8e23bcfc4af837","https://git.kernel.org/stable/c/77de363d9a1c8cd35f20482782c612cda085791a","https://git.kernel.org/stable/c/4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8","https://git.kernel.org/stable/c/7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9","https://git.kernel.org/stable/c/036c1b182f4da65363e79ec0ac276edc6b7296e5"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89712","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89712","identifiers":["CVE-2026-89712"]},"retained":false,"historicalAffected":[]}],"coverage":[]}