CVE-2025-68775

In the Linux kernel, the following vulnerability has been resolved: net/handshake: duplicate handshake cancellations leak socket When a handshake request is cancelled it is removed from the handshake_net->hn_requests list, but it is still present in the handshake_rhashtbl until it is destroyed. If a second cancellation request arrives for the same handshake request, then remove_pending() will return false... and assuming HANDSHAKE_F_REQ_COMPLETED isn't set in req->hr_flags, we'll continue processing through the out_true label, where we put another reference on the sock and a refcount underflow occurs. This can happen for example if a handshake times out - particularly if the SUNRPC client sends the AUTH_TLS probe to the server but doesn't follow it up with the ClientHello due to a problem with tlshd. When the timeout is hit on the server, the server will send a FIN, which triggers a cancellation request via xs_reset_transport(). When the timeout is hit on the client, another cancellation request happens via xs_tls_handshake_sync(). Add a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel path so duplicate cancels can be detected.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663
https://git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f
https://git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be
https://git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659

Configurations

No configuration.

History

19 Oct 2026, 19:17

Type	Values Removed	Values Added
CWE		CWE-662

Information

Published : 2026-01-13 16:15

Updated : 2026-10-19 19:17

NVD link : CVE-2025-68775

Mitre link : CVE-2025-68775

CVE.ORG link : CVE-2025-68775

JSON object : View

Products Affected

No product.

CWE

CWE-662

Improper Synchronization

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When the\ntimeout is hit on the server, the server will send a FIN, which triggers\na cancellation request via xs_reset_transport(). When the timeout is\nhit on the client, another cancellation request happens via\nxs_tls_handshake_sync().\n\nAdd a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel\npath so duplicate cancels can be detected."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet/handshake: las cancelaciones duplicadas de handshake fugan el socket\n\nCuando una solicitud de handshake es cancelada, es eliminada de la lista handshake_net->hn_requests, pero a\u00fan est\u00e1 presente en la handshake_rhashtbl hasta que es destruida.\n\nSi llega una segunda solicitud de cancelaci\u00f3n para la misma solicitud de handshake, entonces remove_pending() devolver\u00e1 falso... y asumiendo que HANDSHAKE_F_REQ_COMPLETED no est\u00e1 establecido en req->hr_flags, continuaremos procesando a trav\u00e9s de la etiqueta out_true, donde ponemos otra referencia en el sock y ocurre un desbordamiento negativo del contador de referencias.\n\nEsto puede ocurrir por ejemplo si un handshake agota el tiempo de espera, particularmente si el cliente SUNRPC env\u00eda la sonda AUTH_TLS al servidor pero no la sigue con el ClientHello debido a un problema con tlshd. Cuando se alcanza el tiempo de espera en el servidor, el servidor enviar\u00e1 un FIN, lo que activa una solicitud de cancelaci\u00f3n a trav\u00e9s de xs_reset_transport(). Cuando se alcanza el tiempo de espera en el cliente, ocurre otra solicitud de cancelaci\u00f3n a trav\u00e9s de xs_tls_handshake_sync().\n\nA\u00f1adir un test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) en la ruta de cancelaci\u00f3n pendiente para que las cancelaciones duplicadas puedan ser detectadas."}], "lastModified": "2026-10-19T19:17:04.537", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}