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.
References
Configurations
Configuration 1 (hide)
|
History
18 Mar 2026, 20:46
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:4.9:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:4.9:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:4.9:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:4.9:rc8:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:* |
|
| First Time |
Linux
Linux linux Kernel |
|
| CWE | CWE-416 | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| References | () https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7 - Patch | |
| References | () https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a - Patch | |
| References | () https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980 - Patch | |
| References | () https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c - Patch | |
| References | () https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66 - Patch | |
| References | () https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc - Patch | |
| References | () https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9 - Patch |
18 Feb 2026, 17:52
| Type | Values Removed | Values Added |
|---|---|---|
| Summary |
|
14 Feb 2026, 17:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-02-14 17:15
Updated : 2026-04-03 14:16
NVD link : CVE-2026-23209
Mitre link : CVE-2026-23209
CVE.ORG link : CVE-2026-23209
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free