{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64281", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.777Z", "datePublished": "2026-07-25T08:49:24.399Z", "dateUpdated": "2026-08-17T04:52:36.535Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:52:36.535Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: wake sq waiters when the transport closes\n\nThreads parked in svc_rdma_sq_wait() on sc_sq_ticket_wait or\nsc_send_wait can hang indefinitely in TASK_UNINTERRUPTIBLE state\nacross transport teardown, pinning svc_xprt references and\nblocking svc_rdma_free().\n\nThe close path sets XPT_CLOSE before invoking xpo_detach and both\nwait_event predicates include an XPT_CLOSE term, but the\npredicates are re-evaluated only on wakeup. sc_sq_ticket_wait has\nno completion-driven wake path; it is advanced solely by the\nchained ticket handoff inside svc_rdma_sq_wait() itself. Without\nan explicit wake at close, parked threads never observe\nXPT_CLOSE, hold their svc_xprt_get reference forever, and\nsvc_rdma_free() blocks on xpt_ref dropping to zero.\n\nTwo close entry points reach this transport. Local teardown runs\nsvc_rdma_detach() from svc_handle_xprt() -> svc_delete_xprt() ->\nxpo_detach() on a worker thread. A remote disconnect arrives at\nsvc_rdma_cma_handler(), which calls svc_xprt_deferred_close():\nthat sets XPT_CLOSE and enqueues the transport but does not\naccess either RDMA waitqueue, so a worker already parked in\nsvc_rdma_sq_wait() never re-evaluates its predicate. With every\nworker parked on this transport, no thread is available to run\nthe local teardown either, and the wake site there is\nunreachable.\n\nIntroduce svc_rdma_xprt_deferred_close(), a thin svcrdma wrapper\nthat calls svc_xprt_deferred_close() and then wakes both\nsc_sq_ticket_wait and sc_send_wait. Convert the svcrdma producers\nthat called svc_xprt_deferred_close() directly:\nsvc_rdma_cma_handler(), qp_event_handler(),\nsvc_rdma_post_send_err(), svc_rdma_wc_send(), the sendto drop\npath, the rw completion error paths, and the recvfrom flush and\nread-list error paths.\n\nWake both waitqueues from svc_rdma_detach() as well. The\nsynchronous svc_xprt_close() path (backchannel ENOTCONN, device\nremoval via svc_rdma_xprt_done) reaches detach without flowing\nthrough svc_xprt_deferred_close() and therefore does not invoke\nthe new helper.\n\n[ cel: add svc_rdma_xprt_deferred_close() to complete the fix ]" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - An unauthenticated peer can reach the vulnerable NFS/RDMA server over an IP-based RDMA connection, including routable iWARP or RoCE deployments.\nAC:L - The attacker controls concurrent request batching, Send Queue pressure, and the remote disconnect that strands waiters, and can repeat attempts without relying on an uncontrollable race.\nPR:N - Malformed RPC/RDMA headers can reach svc_rdma_sq_wait() through the transport-error reply path before RPC authentication, NFS export authorization, or credential validation.\nUI:N - Exploitation requires only attacker-generated RDMA traffic and disconnection; no victim action is required after the service is listening.\nS:U - The vulnerable transport and affected NFS service threads belong to the same host kernel security authority.\nC:N - The defect is a missed wake-up that pins references and does not disclose data or provide a memory-read primitive.\nI:N - No memory corruption, unintended write, or data modification occurs; retained references prevent premature object destruction.\nA:H - Waiters remain indefinitely in TASK_UNINTERRUPTIBLE, and an attacker can park all NFS service workers and block transport teardown or server shutdown, causing complete service availability loss." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/sunrpc/svc_rdma.h", "net/sunrpc/xprtrdma/svc_rdma_recvfrom.c", "net/sunrpc/xprtrdma/svc_rdma_rw.c", "net/sunrpc/xprtrdma/svc_rdma_sendto.c", "net/sunrpc/xprtrdma/svc_rdma_transport.c" ], "versions": [ { "version": "ccc89b9d1ed233349cfe8d87b842e7351b74d8de", "lessThan": "40eedc4253dbda0b29b7961200534dfcecb48ace", "status": "affected", "versionType": "git" }, { "version": "ccc89b9d1ed233349cfe8d87b842e7351b74d8de", "lessThan": "e5248a7426030db1e126363f72afdb3b71339a5c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/sunrpc/svc_rdma.h", "net/sunrpc/xprtrdma/svc_rdma_recvfrom.c", "net/sunrpc/xprtrdma/svc_rdma_rw.c", "net/sunrpc/xprtrdma/svc_rdma_sendto.c", "net/sunrpc/xprtrdma/svc_rdma_transport.c" ], "versions": [ { "version": "7.1", "status": "affected" }, { "version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "7.1", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/40eedc4253dbda0b29b7961200534dfcecb48ace" }, { "url": "https://git.kernel.org/stable/c/e5248a7426030db1e126363f72afdb3b71339a5c" } ], "title": "svcrdma: wake sq waiters when the transport closes", "x_generator": { "engine": "bippy-1.2.0" } } } }