{"api_version":"1","generated_at":"2026-08-22T11:52:58+00:00","cve":"CVE-2026-72221","urls":{"html":"https://cve.report/CVE-2026-72221","api":"https://cve.report/api/cve/CVE-2026-72221.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72221","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72221"},"summary":{"title":"sunrpc: wait for in-flight TLS handshake callback when cancel loses race","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: wait for in-flight TLS handshake callback when cancel loses race\n\nWhen wait_for_completion_interruptible_timeout() in\nsvc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and\ntls_handshake_cancel() then returns false, handshake_complete() has\nwon the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and\nis about to invoke svc_tcp_handshake_done(), but the callback's\nside effects on xpt_flags and on svsk->sk_handshake_done have not\nyet committed.\n\nThe current code reads xpt_flags immediately to decide whether the\nsession succeeded. Two races result.\n\nIf the callback has executed set_bit(XPT_TLS_SESSION) but not yet\nclear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session,\nenqueues the transport, and returns. svc_xprt_received() then\nclears XPT_BUSY, a worker thread picks the transport up, the\ndispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set,\nand xpo_handshake is invoked a second time. That svc_tcp_handshake()\ncalls init_completion(&svsk->sk_handshake_done) while the original\ncallback concurrently calls complete_all() on it, corrupting the\nembedded swait_queue.\n\nIf the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet\nentered svc_tcp_handshake_done(), svc_tcp_handshake() reads\nXPT_TLS_SESSION as clear and tears the connection down even though\nthe handshake is about to succeed.\n\nWait for the callback to commit before inspecting xpt_flags. The\ncompletion is guaranteed to fire because handshake_complete()\ninvokes svc_tcp_handshake_done() unconditionally once it has set\nHANDSHAKE_F_REQ_COMPLETED.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:40","updated_at":"2026-08-17 06:18:23"},"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/a4f878e8ecd729ccf2e50993444e217583adeace","name":"https://git.kernel.org/stable/c/a4f878e8ecd729ccf2e50993444e217583adeace","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b","name":"https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21","name":"https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33","name":"https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9","name":"https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72221","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72221","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3cbf98e2fdf3cb147a95161560cd25987284330 0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3cbf98e2fdf3cb147a95161560cd25987284330 e0f4691d42a54d359d8b64509fd9ab938d4f2a33 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3cbf98e2fdf3cb147a95161560cd25987284330 65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3cbf98e2fdf3cb147a95161560cd25987284330 a4f878e8ecd729ccf2e50993444e217583adeace git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3cbf98e2fdf3cb147a95161560cd25987284330 d00e32f84ca1a77cb67a3fbf59f58dada95f5a21 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.4","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.4 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"72221","cve":"CVE-2026-72221","epss":"0.006260000","percentile":"0.470860000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sunrpc/svcsock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9","status":"affected","version":"b3cbf98e2fdf3cb147a95161560cd25987284330","versionType":"git"},{"lessThan":"e0f4691d42a54d359d8b64509fd9ab938d4f2a33","status":"affected","version":"b3cbf98e2fdf3cb147a95161560cd25987284330","versionType":"git"},{"lessThan":"65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b","status":"affected","version":"b3cbf98e2fdf3cb147a95161560cd25987284330","versionType":"git"},{"lessThan":"a4f878e8ecd729ccf2e50993444e217583adeace","status":"affected","version":"b3cbf98e2fdf3cb147a95161560cd25987284330","versionType":"git"},{"lessThan":"d00e32f84ca1a77cb67a3fbf59f58dada95f5a21","status":"affected","version":"b3cbf98e2fdf3cb147a95161560cd25987284330","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sunrpc/svcsock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.4"},{"lessThan":"6.4","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.4","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 TLS handshake callback when cancel loses race\n\nWhen wait_for_completion_interruptible_timeout() in\nsvc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and\ntls_handshake_cancel() then returns false, handshake_complete() has\nwon the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and\nis about to invoke svc_tcp_handshake_done(), but the callback's\nside effects on xpt_flags and on svsk->sk_handshake_done have not\nyet committed.\n\nThe current code reads xpt_flags immediately to decide whether the\nsession succeeded. Two races result.\n\nIf the callback has executed set_bit(XPT_TLS_SESSION) but not yet\nclear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session,\nenqueues the transport, and returns. svc_xprt_received() then\nclears XPT_BUSY, a worker thread picks the transport up, the\ndispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set,\nand xpo_handshake is invoked a second time. That svc_tcp_handshake()\ncalls init_completion(&svsk->sk_handshake_done) while the original\ncallback concurrently calls complete_all() on it, corrupting the\nembedded swait_queue.\n\nIf the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet\nentered svc_tcp_handshake_done(), svc_tcp_handshake() reads\nXPT_TLS_SESSION as clear and tears the connection down even though\nthe handshake is about to succeed.\n\nWait for the callback to commit before inspecting xpt_flags. The\ncompletion is guaranteed to fire because handshake_complete()\ninvokes svc_tcp_handshake_done() unconditionally once it has set\nHANDSHAKE_F_REQ_COMPLETED."}],"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 - Reachable over TCP by any remote peer of an in-kernel NFS/RPC server (nfsd) via the pre-auth RPC_AUTH_TLS NULL-procedure STARTTLS path that invokes svc_tcp_handshake() on the accepted SUNRPC transport.\nAC:L - The attacker controls both sides of the race by timing TLS client handshake messages against the fixed 5-second SVC_HANDSHAKE_TO and opening many parallel connections to reliably hit the cancel-lost window.\nPR:N - No credentials or export authorization are required; svcauth_tls_accept() accepts empty AUTH_TLS on RPC NULL from any TCP client, and svcauth_unix_set_client() skips IP export checks when rq_proc==0.\nUI:N - Exploitation requires only scripted network connections and TLS client traffic to nfsd; no victim user interaction such as mounting a filesystem or opening a file is needed.\nS:U - Memory corruption occurs in nfsd kernel worker context on the same host; impact is kernel privilege compromise within the server security authority, not a VM escape or IOMMU boundary bypass.\nC:H - A second svc_tcp_handshake() can call init_completion() while svc_tcp_handshake_done() concurrently calls complete_all(), corrupting the embedded swait_queue in heap-allocated svc_sock and enabling arbitrary kernel memory disclosure.\nI:H - Corrupting completion wait-queue metadata in the svc_sock heap object can be leveraged for arbitrary kernel writes and control-flow hijacking to achieve local privilege escalation on the NFS server.\nA:H - The swait_queue corruption can trigger kernel oops/panic, and the alternate race path tears down connections whose TLS handshake is about to succeed, enabling repeatable remote denial-of-service against nfsd."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:41:42.766Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9"},{"url":"https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33"},{"url":"https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b"},{"url":"https://git.kernel.org/stable/c/a4f878e8ecd729ccf2e50993444e217583adeace"},{"url":"https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21"}],"title":"sunrpc: wait for in-flight TLS handshake callback when cancel loses race","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72221","datePublished":"2026-08-15T05:54:14.539Z","dateReserved":"2026-08-09T03:40:39.913Z","dateUpdated":"2026-08-17T05:41:42.766Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:40","lastModifiedDate":"2026-08-17 06:18:23","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":"72221","Ordinal":"1","Title":"sunrpc: wait for in-flight TLS handshake callback when cancel lo","CVE":"CVE-2026-72221","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72221","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: wait for in-flight TLS handshake callback when cancel loses race\n\nWhen wait_for_completion_interruptible_timeout() in\nsvc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and\ntls_handshake_cancel() then returns false, handshake_complete() has\nwon the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and\nis about to invoke svc_tcp_handshake_done(), but the callback's\nside effects on xpt_flags and on svsk->sk_handshake_done have not\nyet committed.\n\nThe current code reads xpt_flags immediately to decide whether the\nsession succeeded. Two races result.\n\nIf the callback has executed set_bit(XPT_TLS_SESSION) but not yet\nclear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session,\nenqueues the transport, and returns. svc_xprt_received() then\nclears XPT_BUSY, a worker thread picks the transport up, the\ndispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set,\nand xpo_handshake is invoked a second time. That svc_tcp_handshake()\ncalls init_completion(&svsk->sk_handshake_done) while the original\ncallback concurrently calls complete_all() on it, corrupting the\nembedded swait_queue.\n\nIf the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet\nentered svc_tcp_handshake_done(), svc_tcp_handshake() reads\nXPT_TLS_SESSION as clear and tears the connection down even though\nthe handshake is about to succeed.\n\nWait for the callback to commit before inspecting xpt_flags. The\ncompletion is guaranteed to fire because handshake_complete()\ninvokes svc_tcp_handshake_done() unconditionally once it has set\nHANDSHAKE_F_REQ_COMPLETED.","Type":"Description","Title":"sunrpc: wait for in-flight TLS handshake callback when cancel lo"}]}}}