CVE 8.8 HIGH

ppp: require CAP_NET_ADMIN in target netns for unattached ioctls_CVE-2026-53075

8.8 / 10
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Description

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.

Basic Information

ID CVE-2026-53075
Source Linux
Published Jun 24, 2026 at 16:30
Modified Jun 28, 2026 at 06:38

Affected Product

Vendor Linux
Product Linux
Version 273ec51dd7ceaa76e038875d85061ec856d8905e
Affected Versions Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 273ec51dd7ceaa76e038875d85061ec856d8905e
Linux Linux 2.6.30

References

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