Описание
In the Linux kernel, the following vulnerability has been resolved:
selinux: check connect-related permissions on TCP Fast Open
Similar to Landlock, SELinux was not updated when TCP Fast Open
support was introduced to ensure connect-related permissions are
checked when using TCP Fast Open. Update its socket_sendmsg() hook to
call selinux_socket_connect() when MSG_FASTOPEN is passed.
A flaw was found in the Linux kernel's Security-Enhanced Linux (SELinux) module. When using TCP Fast Open, SELinux failed to properly check connect-related permissions. This oversight could allow a local attacker to bypass SELinux network access controls, potentially enabling unauthorized network connections that should have been restricted by security policies.
Меры по смягчению последствий
To mitigate this issue, TCP Fast Open (TFO) can be disabled if not required by applications. Disabling TFO prevents the vulnerable code path from being exercised, thereby eliminating the SELinux permission bypass. To disable TCP Fast Open:
- Check the current setting:
sysctl net.ipv4.tcp_fastopen - To disable it temporarily:
sudo sysctl -w net.ipv4.tcp_fastopen=0 - To make the change persistent across reboots, add or modify the following line in
/etc/sysctl.conf:net.ipv4.tcp_fastopen = 0 - Apply the persistent changes:
sudo sysctl -pDisabling TCP Fast Open may impact the performance of applications that utilize this feature for faster connection establishment.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 8 | kernel | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2026:71233 | 24.09.2026 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | kernel | Fixed | RHSA-2026:88687 | 23.10.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:68570 | 17.09.2026 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:68570 | 17.09.2026 |
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Дополнительная информация
Статус:
EPSS
7.3 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: selinux: check connect-related permissions on TCP Fast Open Similar to Landlock, SELinux was not updated when TCP Fast Open support was introduced to ensure connect-related permissions are checked when using TCP Fast Open. Update its socket_sendmsg() hook to call selinux_socket_connect() when MSG_FASTOPEN is passed.
In the Linux kernel, the following vulnerability has been resolved: selinux: check connect-related permissions on TCP Fast Open Similar to Landlock, SELinux was not updated when TCP Fast Open support was introduced to ensure connect-related permissions are checked when using TCP Fast Open. Update its socket_sendmsg() hook to call selinux_socket_connect() when MSG_FASTOPEN is passed.
In the Linux kernel, the following vulnerability has been resolved: s ...
EPSS
7.3 High
CVSS3