Bug 2482614 (CVE-2026-46120) - CVE-2026-46120 kernel: ip6_gre: Use cached t->net in ip6erspan_changelink()
Summary: CVE-2026-46120 kernel: ip6_gre: Use cached t->net in ip6erspan_changelink()
Keywords:
Status: NEW
Alias: CVE-2026-46120
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-28 11:05 UTC by OSIDB Bzimport
Modified: 2026-10-07 05:32 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:57252 0 None None None 2026-08-20 05:13:14 UTC
Red Hat Product Errata RHSA-2026:57253 0 None None None 2026-08-20 04:24:29 UTC
Red Hat Product Errata RHSA-2026:57254 0 None None None 2026-08-20 03:42:22 UTC
Red Hat Product Errata RHSA-2026:61887 0 None None None 2026-09-01 07:30:21 UTC
Red Hat Product Errata RHSA-2026:62609 0 None None None 2026-09-02 12:29:35 UTC
Red Hat Product Errata RHSA-2026:65710 0 None None None 2026-09-09 00:35:47 UTC
Red Hat Product Errata RHSA-2026:77214 0 None None None 2026-10-07 02:32:03 UTC
Red Hat Product Errata RHSA-2026:77215 0 None None None 2026-10-07 05:32:08 UTC

Description OSIDB Bzimport 2026-05-28 11:05:54 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ip6_gre: Use cached t->net in ip6erspan_changelink().

After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of
rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns
ip6gre hash via link_net. ip6erspan_changelink() was not converted in
that series and still uses dev_net(dev), which diverges from the
device's creation netns after IFLA_NET_NS_FD migration.

This re-inserts the tunnel into the wrong per-netns hash. The
original netns keeps a stale entry. When that netns is later
destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a
slab-use-after-free reported by KASAN, followed by a kernel BUG at
net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify().

Reachable from an unprivileged user namespace (unshare --user
--map-root-user --net).

ip6gre_changelink() earlier in the same file already uses the cached
t->net; only ip6erspan_changelink() has the wrong shape.
Comment 1 Keith Grant 2026-05-28 18:14:20 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052815-CVE-2026-46120-1a01@gregkh/T
Comment 5 errata-xmlrpc 2026-08-20 03:42:22 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:57254 https://access.redhat.com/errata/RHSA-2026:57254
Comment 6 errata-xmlrpc 2026-08-20 04:24:29 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:57253 https://access.redhat.com/errata/RHSA-2026:57253
Comment 7 errata-xmlrpc 2026-08-20 05:13:13 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:57252 https://access.redhat.com/errata/RHSA-2026:57252
Comment 8 errata-xmlrpc 2026-09-01 07:30:20 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:61887 https://access.redhat.com/errata/RHSA-2026:61887
Comment 9 errata-xmlrpc 2026-09-02 12:29:35 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:62609 https://access.redhat.com/errata/RHSA-2026:62609
Comment 10 errata-xmlrpc 2026-09-09 00:35:46 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:65710 https://access.redhat.com/errata/RHSA-2026:65710
Comment 11 Jon Orris 2026-10-07 02:32:02 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:77214 https://access.redhat.com/errata/RHSA-2026:77214
Comment 12 Jon Orris 2026-10-07 05:32:06 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:77215 https://access.redhat.com/errata/RHSA-2026:77215
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