Описание
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state
sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which
clears the logger pointer without an RCU grace period. Immediately after,
ops_free_list() frees the per-net state while concurrent packets might
still be executing nf_log_packet() under rcu_read_lock()."
Clear the pointer via .pre_exit to make sure rcu readers have completed
before pernet storage is free'd. The change in nf_log_syslog.c is only
done for consistency: it doesn't use pernet data.
A flaw was found in the Linux kernel's netfilter subsystem. When a network namespace is dismantled, the packet logging component frees memory without waiting for ongoing logging operations to complete, resulting in a use-after-free condition. A local attacker could exploit this flaw during network traffic processing to cause a system crash, leading to a Denial of Service (DoS), or potentially execute arbitrary code.
Меры по смягчению последствий
Prevent the nfnetlink_log kernel module from being loaded by creating a configuration file:
echo "install nfnetlink_log /bin/true" > /etc/modprobe.d/disable-nfnetlink_log.conf
If the module is currently loaded, attempt to unload it:
modprobe -r nfnetlink_log
Caveats: If the module is in use, unloading it dynamically will fail, and a system reboot will be required for the configuration to take effect. Disabling nfnetlink_log prevents netfilter from logging packets via this netlink interface.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Under investigation | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Affected | ||
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2026:76739 | 08.10.2026 |
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Дополнительная информация
Статус:
EPSS
7.8 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which clears the logger pointer without an RCU grace period. Immediately after, ops_free_list() frees the per-net state while concurrent packets might still be executing nf_log_packet() under rcu_read_lock()." Clear the pointer via .pre_exit to make sure rcu readers have completed before pernet storage is free'd. The change in nf_log_syslog.c is only done for consistency: it doesn't use pernet data.
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which clears the logger pointer without an RCU grace period. Immediately after, ops_free_list() frees the per-net state while concurrent packets might still be executing nf_log_packet() under rcu_read_lock()." Clear the pointer via .pre_exit to make sure rcu readers have completed before pernet storage is free'd. The change in nf_log_syslog.c is only done for consistency: it doesn't use pernet data.
netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which clears the logger pointer without an RCU grace period. Immediately after, ops_free_list() frees the per-net state while concurrent packets might still be executing nf_log_packet() under rcu_read_lock()." Clear the pointer via .pre_exit to make sure rcu readers have completed before pernet storage is free'd. The change in nf_log_syslog.c is only done for consistency: it doesn't use pernet data.
EPSS
7.8 High
CVSS3