{"id":"CVE-2026-72222","aliases":[],"url":"https://o3.security/vulnerability/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->hr_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 <= 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->sk_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]","published":"2026-08-15T05:54:15.277Z","modified":"2026-08-16T03:48:37.303905718Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.6.145"}],"fix":null,"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-16T03:48:37.303905718Z"}}