{"id":"CVE-2026-72222","summary":"sunrpc: pin svc_xprt across the asynchronous TLS handshake callback","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: pin svc_xprt across the asynchronous TLS handshake callback\n\nsvc_tcp_handshake() stores the raw svc_xprt pointer in\ntls_handshake_args.ta_data and submits the request through\ntls_server_hello_x509(). The handshake core takes only\nsock_hold(req-\u003ehr_sk); nothing references the embedding struct\nsvc_sock that svc_tcp_handshake_done() reaches via container_of().\n\nTwo close races leave the in-flight callback writing through a freed\nsvc_sock. svc_sock_free() calls tls_handshake_cancel() and discards\nits return value: a false return means handshake_complete() has\nalready set HANDSHAKE_F_REQ_COMPLETED but hp_done() may not have\nfinished, yet svc_sock_free() proceeds to kfree(svsk). The\ncancel-loser fall-through inside svc_tcp_handshake() itself produces\nthe same window: when wait_for_completion_interruptible_timeout()\nreturns \u003c= 0 (timeout or signal) and tls_handshake_cancel() returns\nfalse, the function does not drain, returns, and svc_handle_xprt()\ncalls svc_xprt_received(), which clears XPT_BUSY and can drop the\nlast reference. A concurrent close then runs svc_sock_free() while\nsvc_tcp_handshake_done() is still updating xpt_flags and walking\nsvsk-\u003esk_handshake_done.\n\nThe corruption surfaces as set_bit/clear_bit RMW into the freed\nxpt_flags slab slot and as complete_all() walking and writing the\nfreed wait_queue_head_t list embedded in sk_handshake_done -- a\nslab-corruption primitive, not a benign read. The path is reachable\non any TLS-enabled NFS server whenever a connection close overlaps\nthe tlshd downcall delivery window; the interruptible wait means\nsignal delivery suffices, not just SVC_HANDSHAKE_TO expiry.\n\nTake svc_xprt_get(xprt) immediately before tls_server_hello_x509()\nso the in-flight callback owns its own reference. Release it on the\ntwo edges where the callback is guaranteed not to fire -- submission\nfailure from tls_server_hello_x509() and a successful\ntls_handshake_cancel() -- and at the tail of\nsvc_tcp_handshake_done() after complete_all().\n\n[cel: rewrote commit message to describe the actual change]","modified":"2026-08-18T03:56:39.082858953Z","published":"2026-08-15T05:54:15.277Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72222.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2d4f97d13fff91e0bc539216be88b884b544d49f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3f9ee75a97a769be258784c22b89657acb5ed9bd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4f988f3a2808fb659f3880c282041ff067acad78"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f3b55945dd99f29d83e1965d0141040a35262346"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72222.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72222"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b3cbf98e2fdf3cb147a95161560cd25987284330"},{"fixed":"f3b55945dd99f29d83e1965d0141040a35262346"},{"fixed":"2d4f97d13fff91e0bc539216be88b884b544d49f"},{"fixed":"3f9ee75a97a769be258784c22b89657acb5ed9bd"},{"fixed":"083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f"},{"fixed":"4f988f3a2808fb659f3880c282041ff067acad78"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72222.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.4.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72222.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}