{"api_version":"1","generated_at":"2026-10-06T07:01:50+00:00","cve":"CVE-2026-89536","urls":{"html":"https://cve.report/CVE-2026-89536","api":"https://cve.report/api/cve/CVE-2026-89536.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89536","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89536"},"summary":{"title":"SUNRPC: wait for in-flight client TLS handshake callback","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: wait for in-flight client TLS handshake callback\n\nxs_tls_handshake_sync() gives xs_tls_handshake_done() a reference to the\nlower transport before submitting the handshake request. On timeout or\nsignal, the synchronous waiter drops that reference after calling\ntls_handshake_cancel().\n\nhandshake_req_cancel() returns false when handshake_complete() has\nalready marked the request complete. In that case the completion callback\ncan still be running, so dropping the callback-owned reference in the\nwaiter can free the lower transport before xs_tls_handshake_done() stores\nxprt_err or drops its own reference.\n\nIf cancellation loses to completion, wait until xs_tls_handshake_done()\nsignals handshake_done and let the callback release its reference. This\nmirrors the server-side handshake lifetime handling and keeps the timeout\nor signal return value unchanged.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:36","updated_at":"2026-09-14 13:19:08"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/7fbb6d2ab0391eb8d1f1a68e6bc263ef02cea61b","name":"https://git.kernel.org/stable/c/7fbb6d2ab0391eb8d1f1a68e6bc263ef02cea61b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1de391e8b94e31b45c19c16dbf315e294810c7de","name":"https://git.kernel.org/stable/c/1de391e8b94e31b45c19c16dbf315e294810c7de","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fb43997407bc17ee39bac81ab708101312e255f5","name":"https://git.kernel.org/stable/c/fb43997407bc17ee39bac81ab708101312e255f5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a89dd597458848b463d284b15e42a8078beeb046","name":"https://git.kernel.org/stable/c/a89dd597458848b463d284b15e42a8078beeb046","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/15431820f448e09f8029b670d5c82aa5917d4625","name":"https://git.kernel.org/stable/c/15431820f448e09f8029b670d5c82aa5917d4625","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89536","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89536","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 75eb6af7acdf566c68d61e98e67ee2f235201c02 fb43997407bc17ee39bac81ab708101312e255f5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 75eb6af7acdf566c68d61e98e67ee2f235201c02 15431820f448e09f8029b670d5c82aa5917d4625 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 75eb6af7acdf566c68d61e98e67ee2f235201c02 1de391e8b94e31b45c19c16dbf315e294810c7de git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 75eb6af7acdf566c68d61e98e67ee2f235201c02 7fbb6d2ab0391eb8d1f1a68e6bc263ef02cea61b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 75eb6af7acdf566c68d61e98e67ee2f235201c02 a89dd597458848b463d284b15e42a8078beeb046 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.5","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.157 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"89536","cve":"CVE-2026-89536","epss":"0.006260000","percentile":"0.481070000","score_date":"2026-09-14","updated_at":"2026-09-15 00:00:41"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sunrpc/xprtsock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"fb43997407bc17ee39bac81ab708101312e255f5","status":"affected","version":"75eb6af7acdf566c68d61e98e67ee2f235201c02","versionType":"git"},{"lessThan":"15431820f448e09f8029b670d5c82aa5917d4625","status":"affected","version":"75eb6af7acdf566c68d61e98e67ee2f235201c02","versionType":"git"},{"lessThan":"1de391e8b94e31b45c19c16dbf315e294810c7de","status":"affected","version":"75eb6af7acdf566c68d61e98e67ee2f235201c02","versionType":"git"},{"lessThan":"7fbb6d2ab0391eb8d1f1a68e6bc263ef02cea61b","status":"affected","version":"75eb6af7acdf566c68d61e98e67ee2f235201c02","versionType":"git"},{"lessThan":"a89dd597458848b463d284b15e42a8078beeb046","status":"affected","version":"75eb6af7acdf566c68d61e98e67ee2f235201c02","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sunrpc/xprtsock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.5"},{"lessThan":"6.5","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.157","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.109","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"6.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"6.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"6.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"6.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.5","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: wait for in-flight client TLS handshake callback\n\nxs_tls_handshake_sync() gives xs_tls_handshake_done() a reference to the\nlower transport before submitting the handshake request. On timeout or\nsignal, the synchronous waiter drops that reference after calling\ntls_handshake_cancel().\n\nhandshake_req_cancel() returns false when handshake_complete() has\nalready marked the request complete. In that case the completion callback\ncan still be running, so dropping the callback-owned reference in the\nwaiter can free the lower transport before xs_tls_handshake_done() stores\nxprt_err or drops its own reference.\n\nIf cancellation loses to completion, wait until xs_tls_handshake_done()\nsignals handshake_done and let the callback release its reference. This\nmirrors the server-side handshake lifetime handling and keeps the timeout\nor signal return value unchanged."}],"metrics":[{"cvssV3_1":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - The bug is in the SUNRPC TCP-with-TLS client handshake (xs_tls_handshake_sync), reached when a remote NFS/RPC peer completes RPC-with-TLS; a malicious server or on-path attacker with xprtsec=tls (anonymous TLS) drives handshake_complete() over the network against the client's 10s wait.\nAC:L - The attacker times TLS completion against the fixed XS_TLS_HANDSHAKE_TO window and can force repeated reconnects so tls_handshake_cancel() losing to handshake_complete() is reliably hittable, with no memory-layout guess or other condition outside attacker control.\nPR:N - No privileges on the victim host are required; a remote TLS peer only needs the client to initiate or re-establish an RPC-with-TLS connection, and the handshake runs after AUTH_TLS STARTTLS but before NFS credentials are verified.\nUI:N - No victim action is needed at attack time once an NFS xprtsec=tls/mtls mount exists, because idle disconnect or server-induced reconnect automatically re-enters xs_tcp_tls_setup_socket() and the handshake wait.\nS:U - The use-after-free corrupts kernel heap state in the SUNRPC client on the same host; impact stays within that kernel's security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - When cancel loses, the waiter still xprt_put()s the callback-owned rpc_xprt reference, so sock_xprt can be freed while xs_tls_handshake_done() writes xprt_err and the connect worker still uses lower_xprt, a heap UAF enabling arbitrary disclosure.\nI:H - Use-after-free of rpc_xprt/sock_xprt (ops pointers, wait queues, socket state) allows heap reuse for arbitrary writes and control-flow hijacking, not merely a crash.\nA:H - The extra put can destroy the transport while the handshake waiter and connect worker still touch it, producing a kernel oops/panic or a hang in xprt_destroy waiting on XPRT_LOCKED, denying NFS/RPC service."}]}],"providerMetadata":{"dateUpdated":"2026-09-14T12:00:45.076Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/fb43997407bc17ee39bac81ab708101312e255f5"},{"url":"https://git.kernel.org/stable/c/15431820f448e09f8029b670d5c82aa5917d4625"},{"url":"https://git.kernel.org/stable/c/1de391e8b94e31b45c19c16dbf315e294810c7de"},{"url":"https://git.kernel.org/stable/c/7fbb6d2ab0391eb8d1f1a68e6bc263ef02cea61b"},{"url":"https://git.kernel.org/stable/c/a89dd597458848b463d284b15e42a8078beeb046"}],"title":"SUNRPC: wait for in-flight client TLS handshake callback","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89536","datePublished":"2026-09-11T19:44:14.473Z","dateReserved":"2026-09-11T19:38:34.721Z","dateUpdated":"2026-09-14T12:00:45.076Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:36","lastModifiedDate":"2026-09-14 13:19:08","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89536","Ordinal":"1","Title":"SUNRPC: wait for in-flight client TLS handshake callback","CVE":"CVE-2026-89536","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89536","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: wait for in-flight client TLS handshake callback\n\nxs_tls_handshake_sync() gives xs_tls_handshake_done() a reference to the\nlower transport before submitting the handshake request. On timeout or\nsignal, the synchronous waiter drops that reference after calling\ntls_handshake_cancel().\n\nhandshake_req_cancel() returns false when handshake_complete() has\nalready marked the request complete. In that case the completion callback\ncan still be running, so dropping the callback-owned reference in the\nwaiter can free the lower transport before xs_tls_handshake_done() stores\nxprt_err or drops its own reference.\n\nIf cancellation loses to completion, wait until xs_tls_handshake_done()\nsignals handshake_done and let the callback release its reference. This\nmirrors the server-side handshake lifetime handling and keeps the timeout\nor signal return value unchanged.","Type":"Description","Title":"SUNRPC: wait for in-flight client TLS handshake callback"}]}}}