From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-43403: nsfs: tighten permission checks for ns iteration ioctls
Date: Fri, 8 May 2026 16:22:12 +0200 [thread overview]
Message-ID: <2026050840-CVE-2026-43403-3869@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
nsfs: tighten permission checks for ns iteration ioctls
Even privileged services should not necessarily be able to see other
privileged service's namespaces so they can't leak information to each
other. Use may_see_all_namespaces() helper that centralizes this policy
until the nstree adapts.
The Linux kernel CVE team has assigned CVE-2026-43403 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.12 with commit a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 and fixed in 6.12.78 with commit 3376b345df155ca36d8611857b41ff7d5183fc38
Issue introduced in 6.12 with commit a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 and fixed in 6.18.20 with commit 2f3dea284c761c890d676f77d5e55c0c496b4ef4
Issue introduced in 6.12 with commit a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 and fixed in 6.19.9 with commit 0ad650e60150eda789deca5e78a6a09d26bf8fc9
Issue introduced in 6.12 with commit a1d220d9dafa8d76ba60a784a1016c3134e6a1e8 and fixed in 7.0 with commit e6b899f08066e744f89df16ceb782e06868bd148
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-43403
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
fs/nsfs.c
include/linux/ns_common.h
kernel/nscommon.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/3376b345df155ca36d8611857b41ff7d5183fc38
https://git.kernel.org/stable/c/2f3dea284c761c890d676f77d5e55c0c496b4ef4
https://git.kernel.org/stable/c/0ad650e60150eda789deca5e78a6a09d26bf8fc9
https://git.kernel.org/stable/c/e6b899f08066e744f89df16ceb782e06868bd148
reply other threads:[~2026-05-08 14:24 UTC|newest]
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