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CVE-2026-72221— sunrpc: wait for in-flight TLS handshake callback when cancel loses race

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 6.4版本存在安全漏洞，该漏洞源于svc_tcp_handshake()中TLS握手取消竞争条件，可能导致回调尚未提交时读取xpt_flags，引起握手被重复调用或连接被错误拆除，破坏swait_queue，造成内核崩溃或拒绝服务。

CVSS 9.8 · Critical EPSS 0.63% · P47

Possible ATT&CK Techniques 1 AI

T1053 · Scheduled Task/Job

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux b3cbf98e2fdf3cb147a95161560cd25987284330< 0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9 affected
b3cbf98e2fdf3cb147a95161560cd25987284330< e0f4691d42a54d359d8b64509fd9ab938d4f2a33 affected
b3cbf98e2fdf3cb147a95161560cd25987284330< 65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b affected
b3cbf98e2fdf3cb147a95161560cd25987284330< a4f878e8ecd729ccf2e50993444e217583adeace affected
b3cbf98e2fdf3cb147a95161560cd25987284330< d00e32f84ca1a77cb67a3fbf59f58dada95f5a21 affected
6.4 affected
< 6.4 unaffected
6.6.145≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-72221

Vulnerability Information
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Vulnerability Title
sunrpc: wait for in-flight TLS handshake callback when cancel loses race
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: sunrpc: wait for in-flight TLS handshake callback when cancel loses race When wait_for_completion_interruptible_timeout() in svc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and tls_handshake_cancel() then returns false, handshake_complete() has won the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and is about to invoke svc_tcp_handshake_done(), but the callback's side effects on xpt_flags and on svsk->sk_handshake_done have not yet committed. The current code reads xpt_flags immediately to decide whether the session succeeded. Two races result. If the callback has executed set_bit(XPT_TLS_SESSION) but not yet clear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session, enqueues the transport, and returns. svc_xprt_received() then clears XPT_BUSY, a worker thread picks the transport up, the dispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set, and xpo_handshake is invoked a second time. That svc_tcp_handshake() calls init_completion(&svsk->sk_handshake_done) while the original callback concurrently calls complete_all() on it, corrupting the embedded swait_queue. If the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet entered svc_tcp_handshake_done(), svc_tcp_handshake() reads XPT_TLS_SESSION as clear and tears the connection down even though the handshake is about to succeed. Wait for the callback to commit before inspecting xpt_flags. The completion is guaranteed to fire because handshake_complete() invokes svc_tcp_handshake_done() unconditionally once it has set HANDSHAKE_F_REQ_COMPLETED.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 6.4版本存在安全漏洞，该漏洞源于svc_tcp_handshake()中TLS握手取消竞争条件，可能导致回调尚未提交时读取xpt_flags，引起握手被重复调用或连接被错误拆除，破坏swait_queue，造成内核崩溃或拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux b3cbf98e2fdf3cb147a95161560cd25987284330 ~ 0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9 -
Linux Linux 6.4 -

II. Public POCs for CVE-2026-72221

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III. Intelligence Information for CVE-2026-72221

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Patches & Fixes for CVE-2026-72221 (5)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72436 9.8 CRITICAL netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types
CVE-2026-74394 9.8 CRITICAL RDMA/srpt: fix integer overflow in immediate data length check
CVE-2026-72417 9.8 CRITICAL netfilter: flowtable: Validate iph->ihl in nf_flow_ip4_tunnel_proto()
CVE-2026-72069 9.8 CRITICAL locking/rt: Fix the incorrect RCU protection in rt_spin_unlock()
CVE-2026-72422 9.8 CRITICAL ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE
CVE-2026-72065 9.8 CRITICAL net: mana: Validate the packet length reported by the NIC
CVE-2026-72064 9.8 CRITICAL net: mana: Sync page pool RX frags for CPU
CVE-2026-72429 9.8 CRITICAL ipv6: ioam: fix type confusion of dst_entry
CVE-2026-72251 9.8 CRITICAL netfilter: nf_nat_sip: reload possible stale data pointer
CVE-2026-72234 9.8 CRITICAL batman-adv: access unicast_ttvn skb->data only after skb realloc
CVE-2026-72451 9.8 CRITICAL xfrm: Fix xfrm state cache insertion race
CVE-2026-72041 9.8 CRITICAL espintcp: use sk_msg_free_partial to fix partial send

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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