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.

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History

Sat, 15 Aug 2026 10:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Sat, 15 Aug 2026 06:00:00 +0000

Type Values Removed Values Added
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.
Title sunrpc: wait for in-flight TLS handshake callback when cancel loses race
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-15T05:54:14.539Z

Reserved: 2026-08-09T03:40:39.913Z

Link: CVE-2026-72221

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:21:40.990

Modified: 2026-08-15T06:21:40.990

Link: CVE-2026-72221

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-15T09:45:03Z

Weaknesses