{"id":"CVE-2026-90235","state":"PUBLISHED","title":"sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE\n\nxprtsock replaces and restores sk->sk_data_ready and\nsk->sk_write_space on live sockets with plain stores, and\nxs_udp_do_set_buffer_size() invokes sk->sk_write_space via a plain\nload. These callback pointers are shared with generic socket and\nprotocol paths that may read or invoke them concurrently, so xprtsock\nneeds the same READ_ONCE()/WRITE_ONCE() callback visibility contract\nthat the validated 4022 family applied elsewhere.\n\nWhen SUNRPC takes over an AF_LOCAL, UDP, or TCP socket and later\nrestores the lower-socket callbacks during teardown, another CPU may\nstill hold an earlier callback snapshot. The plain replace/restore\npattern leaves the same visibility hole as the validated 4022 family,\nso a stale snapshot can still invoke xs_data_ready() or\nxs_udp_write_space() after the live callback fields have already been\nrestored to the lower-socket handlers.\n\nUse WRITE_ONCE() for the shared sk_data_ready and sk_write_space\nstores in xs_local_finish_connecting(), xs_udp_finish_connecting(),\nxs_tcp_finish_connecting(), and xs_restore_old_callbacks(). Use\nREAD_ONCE() for the direct sk_write_space invocation in\nxs_udp_do_set_buffer_size(). This matches the required callback\nvisibility contract while leaving adjacent sk_state_change and\nsk_error_report handling unchanged.","publishedAt":"2026-09-17T16:07:41.251Z","updatedAt":"2026-10-30T12:34:53.963Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"6b79b5a0f1c566f0aa6e08c7981826015a0acc4d","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"ed80d009b154aa204f541d390884851b3d4f15ae","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"589f761236e05ff9de1bdfd6a5258f113e6457fe","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"da652cb17f9faeea1fa44b7215e8869a0b10b664","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"d8f0b83753809761a560c4b33249388548ba6e43","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"33930840b5f0a79f826e7c69dc6cd78f72a67481","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/xprtsock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.15","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/xprtsock.c"]}],"references":["https://git.kernel.org/stable/c/6b79b5a0f1c566f0aa6e08c7981826015a0acc4d","https://git.kernel.org/stable/c/ed80d009b154aa204f541d390884851b3d4f15ae","https://git.kernel.org/stable/c/589f761236e05ff9de1bdfd6a5258f113e6457fe","https://git.kernel.org/stable/c/da652cb17f9faeea1fa44b7215e8869a0b10b664","https://git.kernel.org/stable/c/d8f0b83753809761a560c4b33249388548ba6e43","https://git.kernel.org/stable/c/33930840b5f0a79f826e7c69dc6cd78f72a67481"],"weaknesses":[],"ingestedAt":"2026-10-30T12:54:04.478Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90235.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90235","state":"PUBLISHED","datePublished":"2026-09-17T16:07:41.251Z","dateUpdated":"2026-10-30T12:34:53.963Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.794Z"},"containers":{"cna":{"title":"sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE\n\nxprtsock replaces and restores sk->sk_data_ready and\nsk->sk_write_space on live sockets with plain stores, and\nxs_udp_do_set_buffer_size() invokes sk->sk_write_space via a plain\nload. These callback pointers are shared with generic socket and\nprotocol paths that may read or invoke them concurrently, so xprtsock\nneeds the same READ_ONCE()/WRITE_ONCE() callback visibility contract\nthat the validated 4022 family applied elsewhere.\n\nWhen SUNRPC takes over an AF_LOCAL, UDP, or TCP socket and later\nrestores the lower-socket callbacks during teardown, another CPU may\nstill hold an earlier callback snapshot. The plain replace/restore\npattern leaves the same visibility hole as the validated 4022 family,\nso a stale snapshot can still invoke xs_data_ready() or\nxs_udp_write_space() after the live callback fields have already been\nrestored to the lower-socket handlers.\n\nUse WRITE_ONCE() for the shared sk_data_ready and sk_write_space\nstores in xs_local_finish_connecting(), xs_udp_finish_connecting(),\nxs_tcp_finish_connecting(), and xs_restore_old_callbacks(). Use\nREAD_ONCE() for the direct sk_write_space invocation in\nxs_udp_do_set_buffer_size(). This matches the required callback\nvisibility contract while leaving adjacent sk_state_change and\nsk_error_report handling unchanged."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"6b79b5a0f1c566f0aa6e08c7981826015a0acc4d","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"ed80d009b154aa204f541d390884851b3d4f15ae","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"589f761236e05ff9de1bdfd6a5258f113e6457fe","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"da652cb17f9faeea1fa44b7215e8869a0b10b664","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"d8f0b83753809761a560c4b33249388548ba6e43","versionType":"git"},{"version":"a246b0105bbd9a70a698f69baae2042996f2a0e9","status":"affected","lessThan":"33930840b5f0a79f826e7c69dc6cd78f72a67481","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/xprtsock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.15","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/xprtsock.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/6b79b5a0f1c566f0aa6e08c7981826015a0acc4d"},{"url":"https://git.kernel.org/stable/c/ed80d009b154aa204f541d390884851b3d4f15ae"},{"url":"https://git.kernel.org/stable/c/589f761236e05ff9de1bdfd6a5258f113e6457fe"},{"url":"https://git.kernel.org/stable/c/da652cb17f9faeea1fa44b7215e8869a0b10b664"},{"url":"https://git.kernel.org/stable/c/d8f0b83753809761a560c4b33249388548ba6e43"},{"url":"https://git.kernel.org/stable/c/33930840b5f0a79f826e7c69dc6cd78f72a67481"}],"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 - NFSv4.0 SETCLIENTID/SETCLIENTID_CONFIRM (nfsd4_setclientid → gen_callback → setup_callback_client with XPRT_TRANSPORT_TCP) makes nfsd run xs_tcp_finish_connecting; the peer's callback TCP segments hit READ_ONCE(sk_data_ready) in tcp_data_queue and READ_ONCE(sk_write_space) in sock_wfree. NFS client RPC-over-TCP/UDP replies use the same xprtsock callbacks.\nAC:L - The attacker drives both sides: SETCLIENTID_CONFIRM then a later SETCLIENTID or TCP RST forces xs_tcp_finish_connecting versus xs_restore_old_callbacks (nfsd4_process_cb_update → rpc_shutdown_client → xs_reset_transport), while concurrent callback replies and TX skb frees take sock_wfree's lockless sk_write_space snapshot. The race is retryable on new callback sockets.\nPR:N - SETCLIENTID and SETCLIENTID_CONFIRM are ALLOWED_WITHOUT_FH. Typical nfsd deployments accept AUTH_SYS/AUTH_NULL, so a remote peer that can reach TCP/2049 needs no local account or capability on the NFS server to create and tear down the callback xprtsock.\nUI:N - The attacker sends SETCLIENTID/SETCLIENTID_CONFIRM and the callback-channel TCP segments itself. No victim mount or other interactive action is required beyond nfsd already serving NFSv4.0.\nS:U - Stale xs_data_ready or xs_udp_write_space running against a torn-down sock_xprt corrupts kernel memory on the host that owns the RPC socket. This is not a guest-to-host, IOMMU, or other cross-authority escape.\nC:H - A stale xs_data_ready after xs_restore_old_callbacks can still see a non-NULL sk_user_data via xprt_from_sock and call transport->old_data_ready plus read sock_xprt fields, leaking kernel heap once that xprt is reused or freed.\nI:H - The same callback/user_data desync lets xs_write_space queue_work on a freed recv_worker/error_worker and decrement sk_write_pending while xs_reset_transport is in __fput_sync, giving an arbitrary kernel write and control-flow hijack.\nA:H - Use-after-free of sock_xprt in xs_data_ready, xs_udp_write_space, or xs_tcp_write_space from sock_wfree or tcp_data_queue after xs_restore_old_callbacks oopses or panics the kernel even without a full write primitive."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:34:53.963Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.15","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}