{"id":"CVE-2026-72317","revision":"fa7dcf307ffe45ba98d9e11928fbee3c","records":[{"revision":"fa7dcf307ffe45ba98d9e11928fbee3c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72317","aliases":[],"title":"SUNRPC: pin upper rpc_clnt across the TLS connect_worker","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: pin upper rpc_clnt across the TLS connect_worker\n\nThe TLS connect path has a use-after-free: nothing pins the\nupper rpc_clnt across the delayed connect_worker. xs_connect()\nstores task->tk_client in sock_xprt::clnt as a raw pointer\nand queues the worker; for TLS-secured transports that worker\nis xs_tcp_tls_setup_socket(), which reads several fields out\nof the saved pointer (cl_timeout, cl_program, cl_prog,\ncl_vers, cl_cred, cl_stats) to construct the args for the\ninner handshake rpc_clnt.\n\nThe xprt does not reference the rpc_clnt; the rpc_clnt\nreferences the xprt. xs_destroy() does cancel the\nconnect_worker, but it runs only when the xprt's refcount\ndrops to zero, which cannot happen until the rpc_clnt\nreleases its cl_xprt reference in rpc_free_client_work().\nWhen a TLS handshake fails fatally (for example, an mTLS\nmount whose client cert does not match the server), the\nconnecting task is woken with -EACCES and exits, the mount\ncaller invokes rpc_shutdown_client(), and the upper rpc_clnt\nis freed before the queued connect_worker fires.\nxs_tcp_tls_setup_socket() then dereferences the freed clnt,\nproducing the refcount_t underflow Michael Nemanov reported.\n\nTake a reference on the upper rpc_clnt in xs_connect() for\nTLS transports via a new rpc_hold_client() helper, and drop\nit in the connect_worker's exit path with rpc_release_client().\nThe xprt_lock_connect() / xprt_unlock_connect() pairing\nalready serialises xs_connect() with xs_tcp_tls_setup_socket(),\nso the take and release are balanced one-for-one.\n\nThe non-TLS connect worker (xs_tcp_setup_socket) never reads\nsock_xprt::clnt, so leave that path alone and avoid the\nclnt-holds-xprt-holds-clnt cycle that would otherwise prevent\nxprt destruction.","state":0,"publishedAt":"2026-08-15T05:55:31.022+00:00","modifiedAt":"2026-10-16T18:55:17.145+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                        \"include/linux/sunrpc/clnt.h\",\n                        \"net/sunrpc/clnt.c\",\n                        \"net/sunrpc/xprtsock.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"75eb6af7acdf566c68d61e98e67ee2f235201c02\",\n                            \"lessThan\": \"79cd550f8c884523b604fbfa43eb02def74d6224\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"75eb6af7acdf566c68d61e98e67ee2f235201c02\",\n                            \"lessThan\": \"7a65b41b657b71d5a77861f47dd13eb4bc8e10d0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"75eb6af7acdf566c68d61e98e67ee2f235201c02\",\n                            \"lessThan\": \"5b0427ba582d143a364301f825f4e32272f06d2d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"75eb6af7acdf566c68d61e98e67ee2f235201c02\",\n                            \"lessThan\": \"d49f6d098ed48775b9d27a9f9c5c220fdf76f102\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"75eb6af7acdf566c68d61e98e67ee2f235201c02\",\n                            \"lessThan\": \"46bc86c833956219bbfd246c1ffd832a479c5199\",\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                        \"include/linux/sunrpc/clnt.h\",\n                        \"net/sunrpc/clnt.c\",\n                        \"net/sunrpc/xprtsock.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.5\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.5\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.97\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.40\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.5\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\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/79cd550f8c884523b604fbfa43eb02def74d6224","https://git.kernel.org/stable/c/7a65b41b657b71d5a77861f47dd13eb4bc8e10d0","https://git.kernel.org/stable/c/5b0427ba582d143a364301f825f4e32272f06d2d","https://git.kernel.org/stable/c/d49f6d098ed48775b9d27a9f9c5c220fdf76f102","https://git.kernel.org/stable/c/46bc86c833956219bbfd246c1ffd832a479c5199"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72317","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72317","identifiers":["CVE-2026-72317"]},"retained":false,"historicalAffected":[]}],"coverage":[]}