CVE-2026-74696

In the Linux kernel, the following vulnerability has been resolved: tcp: fix TFO max_qlen accounting across reuseport migration A listener's TCP_FASTOPEN max_qlen stops being accurate and lets through far more pending Fast Open requests than it was configured for. This only shows up with SO_REUSEPORT listener migration, where closing a listener hands its still-pending TFO children over to a surviving one. fastopenq.qlen is charged in tcp_fastopen_create_child() when the child is created and uncharged in reqsk_fastopen_remove() when the handshake completes. The uncharge follows rsk_listener of the request the child points at, and inet_reqsk_clone() has repointed the child at a new request owned by the new listener, so the ++ and the -- land on two different sockets. The new listener's qlen drifts negative and its limit no longer binds. Charge the new listener during migration, like reqsk_queue_migrated() already does for queue->young and queue->qlen.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/585fc5247d14939a561056aa2addd9b7c2b1f670
https://git.kernel.org/stable/c/6e10ee56524a26b250229ad348637825646ddb88
https://git.kernel.org/stable/c/a0ab2ba83e35159d81cec830a92e885ecf8139be
https://git.kernel.org/stable/c/a66e869cf0c90c1e47ae75f72b6482acbfc808ff
https://git.kernel.org/stable/c/b6247e0f96bd825ffb2005257f6177b5e642dee6
https://git.kernel.org/stable/c/d974618b2097453778389d385e3741629c40e0a3
https://git.kernel.org/stable/c/e98f0d80b9cccb5f828425d2004f9686e7d1ae24

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-22 16:16

Updated : 2026-08-25 06:18

NVD link : CVE-2026-74696

Mitre link : CVE-2026-74696

CVE.ORG link : CVE-2026-74696

JSON object : View

Products Affected

No product.

CWE

No CWE.

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The uncharge follows rsk_listener of the request the child\npoints at, and inet_reqsk_clone() has repointed the child at a new\nrequest owned by the new listener, so the ++ and the -- land on two\ndifferent sockets. The new listener's qlen drifts negative and its\nlimit no longer binds.\n\nCharge the new listener during migration, like reqsk_queue_migrated()\nalready does for queue->young and queue->qlen."}], "lastModified": "2026-08-25T06:18:53.137", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}