{"id":"CVE-2026-72222","title":"sunrpc: pin svc_xprt across the asynchronous TLS handshake callback","summary":"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 r…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < f3b55945dd99f29d83e1965d0141040a35262346","Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 2d4f97d13fff91e0bc539216be88b884b544d49f","Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 3f9ee75a97a769be258784c22b89657acb5ed9bd","Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f","Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 4f988f3a2808fb659f3880c282041ff067acad78","Linux 6.4"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:44:02.358946Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:45:02.369Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72222","references":[{"url":"https://git.kernel.org/stable/c/f3b55945dd99f29d83e1965d0141040a35262346"},{"url":"https://git.kernel.org/stable/c/2d4f97d13fff91e0bc539216be88b884b544d49f"},{"url":"https://git.kernel.org/stable/c/3f9ee75a97a769be258784c22b89657acb5ed9bd"},{"url":"https://git.kernel.org/stable/c/083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f"},{"url":"https://git.kernel.org/stable/c/4f988f3a2808fb659f3880c282041ff067acad78"}],"tags":["cve.org"],"epss":0.00635,"epssPercentile":0.49341,"ingestedAt":"2026-10-16T19:46:24.421Z","slug":"CVE-2026-72222","body":"## Overview\n\nIn 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]\n\n## Affected\n\n- `Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < f3b55945dd99f29d83e1965d0141040a35262346`\n- `Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 2d4f97d13fff91e0bc539216be88b884b544d49f`\n- `Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 3f9ee75a97a769be258784c22b89657acb5ed9bd`\n- `Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f`\n- `Linux >= b3cbf98e2fdf3cb147a95161560cd25987284330 < 4f988f3a2808fb659f3880c282041ff067acad78`\n- `Linux 6.4`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}