{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72222","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-09T03:40:39.913Z","datePublished":"2026-08-15T05:54:15.277Z","dateUpdated":"2026-08-17T05:41:44.196Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:41:44.196Z"},"descriptions":[{"lang":"en","value":"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]"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The flaw is in nfsd's server-side SUNRPC/TCP TLS handshake (net/sunrpc/svcsock.c), reached when a remote peer connects to port 2049 and sends a pre-authentication AUTH_TLS NULL STARTTLS probe that triggers svc_tcp_handshake() via svcauth_tls_accept().\nAC:L - The attacker controls both sides of the race by initiating AUTH_TLS handshakes and concurrently resetting/closing TCP or waiting for SVC_HANDSHAKE_TO while tlshd delivers completion; repeated parallel connections make the overlap window reliably reachable.\nPR:N - AUTH_TLS is processed on RPC procedure 0 before credentials are verified, so an unauthenticated remote client can reach svc_tcp_handshake() and the asynchronous callback without any account, export access, or kernel capability.\nUI:N - nfsd worker threads automatically accept the TCP connection, process the STARTTLS probe, run the TLS handshake, and handle teardown/completion callbacks without any local user or administrator action.\nS:U - Exploitation corrupts kernel memory on the NFS server host itself and does not cross a VM-guest/host, sandbox, or IOMMU security boundary; impact stays within the kernel's security authority.\nC:H - svc_tcp_handshake_done() use-after-frees svc_sock and performs set_bit/clear_bit RMW on freed xpt_flags plus complete_all() on freed sk_handshake_done, a slab-corruption UAF that can disclose arbitrary kernel memory.\nI:H - The same UAF delivers attacker-timed writes into reclaimed slab slots through atomic bit operations and wait-queue list updates, enabling heap grooming and further kernel memory corruption for arbitrary modification or code execution.\nA:H - Slab corruption and UAF during handshake completion can cause kernel oops/panic, and unauthenticated remote peers can trigger the fault repeatedly by overlapping TLS handshake completion with connection close."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svcsock.c"],"versions":[{"version":"b3cbf98e2fdf3cb147a95161560cd25987284330","lessThan":"f3b55945dd99f29d83e1965d0141040a35262346","status":"affected","versionType":"git"},{"version":"b3cbf98e2fdf3cb147a95161560cd25987284330","lessThan":"2d4f97d13fff91e0bc539216be88b884b544d49f","status":"affected","versionType":"git"},{"version":"b3cbf98e2fdf3cb147a95161560cd25987284330","lessThan":"3f9ee75a97a769be258784c22b89657acb5ed9bd","status":"affected","versionType":"git"},{"version":"b3cbf98e2fdf3cb147a95161560cd25987284330","lessThan":"083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f","status":"affected","versionType":"git"},{"version":"b3cbf98e2fdf3cb147a95161560cd25987284330","lessThan":"4f988f3a2808fb659f3880c282041ff067acad78","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svcsock.c"],"versions":[{"version":"6.4","status":"affected"},{"version":"0","lessThan":"6.4","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.97","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.40","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.5","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":"6.4","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"7.2"}]}]}],"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"}],"title":"sunrpc: pin svc_xprt across the asynchronous TLS handshake callback","x_generator":{"engine":"bippy-1.2.0"}}}}