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CVE-2026-74696

Unknown

Last modified

CVE-2026-74696 is a vulnerability of currently unknown severity. 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.

Description

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 54b92e84193749c9968aff2dd46e3b0f42643e18, < e98f0d80b9cccb5f828425d2004f9686e7d1ae24; >= 54b92e84193749c9968aff2dd46e3b0f42643e18, < b6247e0f96bd825ffb2005257f6177b5e642dee6; >= 54b92e84193749c9968aff2dd46e3b0f42643e18, < 585fc5247d14939a561056aa2addd9b7c2b1f670; >= 54b92e84193749c9968aff2dd46e3b0f42643e18, < 6e10ee56524a26b250229ad348637825646ddb88; >= 54b92e84193749c9968aff2dd46e3b0f42643e18, < a66e869cf0c90c1e47ae75f72b6482acbfc808ff; >= 54b92e84193749c9968aff2dd46e3b0f42643e18, < d974618b2097453778389d385e3741629c40e0a3; >= 54b92e84193749c9968aff2dd46e3b0f42643e18, < a0ab2ba83e35159d81cec830a92e885ecf8139be
LinuxLinux5.14

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is 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.
How severe is CVE-2026-74696?
Severity scoring for CVE-2026-74696 is pending analysis.
How do I fix CVE-2026-74696?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST