In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix error recovery in macvlan_common_newlink()
valis provided a nice repro to crash the kernel:
ip link add p1 type veth peer p2
ip link set address 00:00:00:00:00:20 dev p1
ip link set up dev p1
ip link set up dev p2
ip link add mv0 link p2 type macvlan mode source
ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20
ping -c1 -I p1 1.2.3.4
He also gave a very detailed analysis:
<quote valis>
The issue is triggered when a new macvlan link is created with
MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or
MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan
port and register_netdevice() called from macvlan_common_newlink()
fails (e.g. because of the invalid link name).
In this case macvlan_hash_add_source is called from
macvlan_change_sources() / macvlan_common_newlink():
This adds a reference to vlan to the port's vlan_source_hash using
macvlan_source_entry.
vlan is a pointer to the priv data of the link that is being created.
When register_netdevice() fails, the error is returned from
macvlan_newlink() to rtnl_newlink_create():
if (ops->newlink)
err = ops->newlink(dev, ¶ms, extack);
else
err = register_netdevice(dev);
if (err < 0) {
free_netdev(dev);
goto out;
}
and free_netdev() is called, causing a kvfree() on the struct
net_device that is still referenced in the source entry attached to
the lower device's macvlan port.
Now all packets sent on the macvlan port with a matching source mac
address will trigger a use-after-free in macvlan_forward_source().
</quote valis>
With all that, my fix is to make sure we call macvlan_flush_sources()
regardless of @create value whenever "goto destroy_macvlan_port;"
path is taken.
Many thanks to valis for following up on this issue.
GHSA-89j4-f3cq-gm32
In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix error recovery...
https://github.com/advisories/GHSA-89j4-f3cq-gm32In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix error recovery in macvlan_common_newlink()
valis provided a nice repro to crash the kernel:
ip link add p1 type veth peer p2
ip link set address 00:00:00:00:00:20 dev p1
ip link set up dev p1
ip link set up dev p2
ip link add mv0 link p2 type macvlan mode source
ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20
ping -c1 -I p1 1.2.3.4
He also gave a very detailed analysis:
The issue is triggered when a new macvlan link is created with
MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or
MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan
port and register_netdevice() called from macvlan_common_newlink()
fails (e.g. because of the invalid link name).
In this case macvlan_hash_add_source is called from
macvlan_change_sources() / macvlan_common_newlink():
This adds a reference to vlan to the port's vlan_source_hash using
macvlan_source_entry.
vlan is a pointer to the priv data of the link that is being created.
When register_netdevice() fails, the error is returned from
macvlan_newlink() to rtnl_newlink_create():
if (ops->newlink)
err = ops->newlink(dev, ¶ms, extack);
else
err = register_netdevice(dev);
if (err < 0) {
free_netdev(dev);
goto out;
}
and free_netdev() is called, causing a kvfree() on the struct
net_device that is still referenced in the source entry attached to
the lower device's macvlan port.
Now all packets sent on the macvlan port with a matching source mac
address will trigger a use-after-free in macvlan_forward_source().
</quote valis>
With all that, my fix is to make sure we call macvlan_flush_sources()
regardless of @create value whenever "goto destroy_macvlan_port;"
path is taken.
Many thanks to valis for following up on this issue.
Click to expand
{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-23209",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"dateUpdated": "2026-02-14T16:27:31.175Z",
"dateReserved": "2026-01-13T15:37:45.986Z",
"datePublished": "2026-02-14T16:27:31.175Z",
"state": "PUBLISHED"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-02-14T16:27:31.175Z"
},
"title": "macvlan: fix error recovery in macvlan_common_newlink()",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: fix error recovery in macvlan_common_newlink()\n\nvalis provided a nice repro to crash the kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nHe also gave a very detailed analysis:\n\n<quote valis>\n\nThe issue is triggered when a new macvlan link is created with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\n\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\n\nThis adds a reference to vlan to the port's vlan_source_hash using\nmacvlan_source_entry.\n\nvlan is a pointer to the priv data of the link that is being created.\n\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\n\n if (ops->newlink)\n err = ops->newlink(dev, ¶ms, extack);\n else\n err = register_netdevice(dev);\n if (err < 0) {\n free_netdev(dev);\n goto out;\n }\n\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device's macvlan port.\n\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n\n</quote valis>\n\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\n\nMany thanks to valis for following up on this issue."
}
],
"affected": [
{
"vendor": "Linux",
"product": "Linux",
"programFiles": [
"drivers/net/macvlan.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"defaultStatus": "unaffected",
"versions": [
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "da5c6b8ae47e414be47e5e04def15b25d5c962dc"
},
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a"
},
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "c43d0e787cbba569ec9d11579ed370b50fab6c9c"
},
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "11ba9f0dc865136174cb98834280fb21bbc950c7"
},
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "986967a162142710076782d5b93daab93a892980"
},
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66"
},
{
"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280",
"status": "affected",
"versionType": "git",
"lessThan": "f8db6475a83649689c087a8f52486fcc53e627e9"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"programFiles": [
"drivers/net/macvlan.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"defaultStatus": "affected",
"versions": [
{
"version": "4.9",
"status": "affected"
},
{
"version": "0",
"status": "unaffected",
"versionType": "semver",
"lessThan": "4.9"
},
{
"version": "5.10.250",
"status": "unaffected",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"version": "5.15.200",
"status": "unaffected",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"version": "6.1.163",
"status": "unaffected",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"version": "6.6.124",
"status": "unaffected",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"version": "6.12.70",
"status": "unaffected",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"version": "6.18.10",
"status": "unaffected",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"version": "6.19",
"status": "unaffected",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc"
},
{
"url": "https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a"
},
{
"url": "https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c"
},
{
"url": "https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7"
},
{
"url": "https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980"
},
{
"url": "https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66"
},
{
"url": "https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9"
}
]
}
}
}