In the Linux kernel, the following vulnerability has been resolved: tcp: restrict SO_ATTACH_FILTER to priv users This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets to users with CAP_NET_ADMIN capability. This blocks potential side-channel attack where an unprivileged application attaches a filter to leak TCP sequence/acknowledgment numbers.

A flaw was found in the Linux kernel's handling of TCP sockets. An unprivileged application can exploit this vulnerability by attaching a Berkeley Packet Filter (BPF) using the SO_ATTACH_FILTER option. This allows the application to conduct a side-channel attack, leading to the leakage of sensitive TCP sequence and acknowledgment numbers. This information disclosure could potentially be used to aid further attacks.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Affected kernel Red Hat Enterprise Linux 7 Affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-53236 https://nvd.nist.gov/vuln/detail/CVE-2026-53236 https://lore.kernel.org/linux-cve-announce/2026062510-CVE-2026-53236-45bc@gregkh/T