Описание
In the Linux kernel, the following vulnerability has been resolved:
ppp: require CAP_NET_ADMIN in target netns for unattached ioctls
/dev/ppp open is currently authorized against file->f_cred->user_ns,
while unattached administrative ioctls operate on current->nsproxy->net_ns.
As a result, a local unprivileged user can create a new user namespace
with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace,
and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against
an inherited network namespace.
Require CAP_NET_ADMIN in the user namespace that owns the target network
namespace before handling unattached PPP administrative ioctls.
This preserves normal pppd operation in the network namespace it is
actually privileged in, while rejecting the userns-only inherited-netns
case.
A flaw was found in the Linux kernel's Point-to-Point Protocol (PPP) subsystem. A local unprivileged user can exploit this vulnerability by creating a new user namespace and bypassing authorization checks for unattached administrative input/output controls (ioctls). This allows the user to perform unauthorized administrative operations on an inherited network namespace, potentially leading to privilege escalation.
Отчет
PPP unattached administrative ioctls used a capability check that could be satisfied in a different user namespace than the one owning the target network namespace. A local unprivileged user can create a new user namespace, gain CAP_NET_ADMIN only there, and still operate on an inherited network namespace through PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN. For the CVSS the PR:L is used for the paranoid score because local code execution by an unprivileged user is enough when unprivileged user namespaces are enabled. The issue is not network reachable and is triggered through the local /dev/ppp control interface. Impact is an authorization bypass for PPP administrative operations, with possible network configuration integrity impact and denial of service in the target netns.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 9 | kernel | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2026:64775 | 08.09.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:68532 | 17.09.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:68531 | 17.09.2026 |
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Дополнительная информация
Статус:
EPSS
6.6 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ppp: require CAP_NET_ADMIN in target netns for unattached ioctls /dev/ppp open is currently authorized against file->f_cred->user_ns, while unattached administrative ioctls operate on current->nsproxy->net_ns. As a result, a local unprivileged user can create a new user namespace with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace, and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against an inherited network namespace. Require CAP_NET_ADMIN in the user namespace that owns the target network namespace before handling unattached PPP administrative ioctls. This preserves normal pppd operation in the network namespace it is actually privileged in, while rejecting the userns-only inherited-netns case.
In the Linux kernel, the following vulnerability has been resolved: ppp: require CAP_NET_ADMIN in target netns for unattached ioctls /dev/ppp open is currently authorized against file->f_cred->user_ns, while unattached administrative ioctls operate on current->nsproxy->net_ns. As a result, a local unprivileged user can create a new user namespace with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace, and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against an inherited network namespace. Require CAP_NET_ADMIN in the user namespace that owns the target network namespace before handling unattached PPP administrative ioctls. This preserves normal pppd operation in the network namespace it is actually privileged in, while rejecting the userns-only inherited-netns case.
ppp: require CAP_NET_ADMIN in target netns for unattached ioctls
In the Linux kernel, the following vulnerability has been resolved: p ...
In the Linux kernel, the following vulnerability has been resolved: ppp: require CAP_NET_ADMIN in target netns for unattached ioctls /dev/ppp open is currently authorized against file->f_cred->user_ns, while unattached administrative ioctls operate on current->nsproxy->net_ns. As a result, a local unprivileged user can create a new user namespace with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace, and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against an inherited network namespace. Require CAP_NET_ADMIN in the user namespace that owns the target network namespace before handling unattached PPP administrative ioctls. This preserves normal pppd operation in the network namespace it is actually privileged in, while rejecting the userns-only inherited-netns case.
EPSS
6.6 Medium
CVSS3