Red Hat Kernel Updates Fix TCP Fast Open Use-After-Free in RHEL 8 and 9

Red Hat released Important-rated kernel updates for specialized RHEL 8.8 and RHEL 9.2 support channels, addressing TCP Fast Open (TFO) flaws including CVE-2025-40186. A low-privileged local attacker could close a listener while tcp_conn_request() processes a TFO socket, triggering use-after-free and double-free conditions that may cause a kernel panic or potentially enable privilege escalation. The RHEL 8.8 update also fixes CVE-2025-39955 and the memory-management race condition tracked as CVE-2023-53401; the RHEL 9.2 update additionally remediates qla2xxx driver flaw CVE-2023-53322 and cfg80211 Wi-Fi flaw CVE-2025-39864.

Affected deployments include RHEL 8.8 Extended Life Cycle Long Life, TUS, and SAP update channels on x86_64 and Power LE, and RHEL 9.2 AUS, SAP, four-year update, and Extended Life Cycle offerings across x86_64, ARM64, IBM Z, and Power LE. Red Hat supplied fixed kernel builds 4.18.0-477.123.1.el8_8 for the covered RHEL 8.8 channels and 5.14.0-284.150.1.el9_2 for RHEL 9.2; administrators should install the applicable packages and reboot systems to activate the fixes.