CVE-2025-68188

kernel: tcp: use dst_dev_rcu() in tcp_fastopen_active_disable_ofo_check()

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Severity

Moderate

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · December 16, 2025

Updated · June 30, 2026

Description

A potential use-after-free was found in the TCP Fast Open implementation in the Linux kernel. The tcp_fastopen_active_disable_ofo_check() function accesses dst_dev()->flags without proper RCU protection, which could lead to accessing a freed network device structure.

Statement

This is a correctness fix to use proper RCU primitives. The race window is narrow and triggering it requires specific network conditions during TCP Fast Open operations.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE-821 · Incorrect Synchronization