Linux Kernel TCP stack Vulnerability Rated 7.5 CVSS

Status: UPDATED  |  Advisory ID: CVE-2026-74696

Key Details

Affected Products, Subsystems & Sectors

What to Know

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. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References