{"id":"CVE-2026-89546","revision":"5ee6b8861922460597d3b4d17a5c631f","records":[{"revision":"5ee6b8861922460597d3b4d17a5c631f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89546","aliases":[],"title":"SUNRPC: close backchannel before destroying callback service","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: close backchannel before destroying callback service\n\nA backchannel receive can complete a request while the NFS callback\nservice is being torn down.  xprt_complete_bc_request() removes the\nrequest from bc_pa_list, drops bc_alloc_count, marks the request in use,\nand then asks xprt_enqueue_bc_request() to hand it to the callback\nservice.\n\nIf teardown has already cleared xprt->bc_serv, xprt_enqueue_bc_request()\ncurrently returns without enqueueing or freeing the committed request.\nThe xprt_get() taken on entry is leaked as well.  If the producer wins\nthe race before bc_serv is cleared, it can also enqueue onto sv_cb_list\nafter nfs_callback_down() has stopped the callback threads, leaving the\nrequest linked to a svc_serv that is about to be freed.\n\nClose the producer side before callback threads are stopped.  Add\nxprt_svc_shutdown_bc() to clear xprt->bc_serv under bc_pa_lock, and call\nit on callback shutdown and callback-start failure before stopping the\nservice threads.  Requests that lose the NULL transition in\nxprt_enqueue_bc_request() are released through the normal backchannel\nfree path after balancing bc_slot_count.  Finally, drain any remaining\nsv_cb_list requests after the callback threads have stopped and before\nsvc_destroy() frees the service.","state":0,"publishedAt":"2026-09-11T19:44:21.898+00:00","modifiedAt":"2026-10-19T08:48:37.92+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/nfs/callback.c\",\n                        \"include/linux/sunrpc/bc_xprt.h\",\n                        \"net/sunrpc/backchannel_rqst.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"441244d4273a8037b265fd254dfdaca5fa736ee2\",\n                            \"lessThan\": \"6debde9e3e6ae21dcca75837b4247b13ca4ea2b8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"441244d4273a8037b265fd254dfdaca5fa736ee2\",\n                            \"lessThan\": \"3674f780f47d2906b5a0f7199b66973067bdfeca\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\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/nfs/callback.c\",\n                        \"include/linux/sunrpc/bc_xprt.h\",\n                        \"net/sunrpc/backchannel_rqst.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.19\",\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/6debde9e3e6ae21dcca75837b4247b13ca4ea2b8","https://git.kernel.org/stable/c/3674f780f47d2906b5a0f7199b66973067bdfeca"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89546","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89546","identifiers":["CVE-2026-89546"]},"retained":false,"historicalAffected":[]}],"coverage":[]}