In the Linux kernel, the following vulnerability has been resolved:
ethtool: Fix uninitialized number of lanes
It is not possible to set the number of lanes when setting link modes
using the legacy IOCTL ethtool interface. Since 'struct
ethtool_link_ksettings' is not initialized in this path, drivers receive
an uninitialized number of lanes in 'struct
ethtool_link_ksettings::lanes'.
When this information is later queried from drivers, it results in the
ethtool code making decisions based on uninitialized memory, leading to
the following KMSAN splat [1]. In practice, this most likely only
happens with the tun driver that simply returns whatever it got in the
set operation.
As far as I can tell, this uninitialized memory is not leaked to user
space thanks to the 'ethtool_ops->cap_link_lanes_supported' check in
linkmodes_prepare_data().
Fix by initializing the structure in the IOCTL path. Did not find any
more call sites that pass an uninitialized structure when calling
'ethtool_ops::set_link_ksettings()'.
[1]
BUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
BUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was stored to memory at:
tun_get_link_ksettings+0x37/0x60 drivers/net/tun.c:3544
__ethtool_get_link_ksettings+0x17b/0x260 net/ethtool/ioctl.c:441
ethnl_set_linkmodes+0xee/0x19d0 net/ethtool/linkmodes.c:327
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was stored to memory at:
tun_set_link_ksettings+0x37/0x60 drivers/net/tun.c:3553
ethtool_set_link_ksettings+0x600/0x690 net/ethtool/ioctl.c:609
__dev_ethtool net/ethtool/ioctl.c:3024 [inline]
dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078
dev_ioctl+0xb07/0x1270 net/core/dev_ioctl.c:524
sock_do_ioctl+0x295/0x540 net/socket.c:1213
sock_i
---truncated---
ethtool: Fix uninitialized number of lanes
It is not possible to set the number of lanes when setting link modes
using the legacy IOCTL ethtool interface. Since 'struct
ethtool_link_ksettings' is not initialized in this path, drivers receive
an uninitialized number of lanes in 'struct
ethtool_link_ksettings::lanes'.
When this information is later queried from drivers, it results in the
ethtool code making decisions based on uninitialized memory, leading to
the following KMSAN splat [1]. In practice, this most likely only
happens with the tun driver that simply returns whatever it got in the
set operation.
As far as I can tell, this uninitialized memory is not leaked to user
space thanks to the 'ethtool_ops->cap_link_lanes_supported' check in
linkmodes_prepare_data().
Fix by initializing the structure in the IOCTL path. Did not find any
more call sites that pass an uninitialized structure when calling
'ethtool_ops::set_link_ksettings()'.
[1]
BUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
BUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was stored to memory at:
tun_get_link_ksettings+0x37/0x60 drivers/net/tun.c:3544
__ethtool_get_link_ksettings+0x17b/0x260 net/ethtool/ioctl.c:441
ethnl_set_linkmodes+0xee/0x19d0 net/ethtool/linkmodes.c:327
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was stored to memory at:
tun_set_link_ksettings+0x37/0x60 drivers/net/tun.c:3553
ethtool_set_link_ksettings+0x600/0x690 net/ethtool/ioctl.c:609
__dev_ethtool net/ethtool/ioctl.c:3024 [inline]
dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078
dev_ioctl+0xb07/0x1270 net/core/dev_ioctl.c:524
sock_do_ioctl+0x295/0x540 net/socket.c:1213
sock_i
---truncated---
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 10 Dec 2025 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Tue, 09 Dec 2025 00:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ethtool: Fix uninitialized number of lanes It is not possible to set the number of lanes when setting link modes using the legacy IOCTL ethtool interface. Since 'struct ethtool_link_ksettings' is not initialized in this path, drivers receive an uninitialized number of lanes in 'struct ethtool_link_ksettings::lanes'. When this information is later queried from drivers, it results in the ethtool code making decisions based on uninitialized memory, leading to the following KMSAN splat [1]. In practice, this most likely only happens with the tun driver that simply returns whatever it got in the set operation. As far as I can tell, this uninitialized memory is not leaked to user space thanks to the 'ethtool_ops->cap_link_lanes_supported' check in linkmodes_prepare_data(). Fix by initializing the structure in the IOCTL path. Did not find any more call sites that pass an uninitialized structure when calling 'ethtool_ops::set_link_ksettings()'. [1] BUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline] BUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333 ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline] ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333 ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640 genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline] genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065 netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577 genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg net/socket.c:747 [inline] ____sys_sendmsg+0xa24/0xe40 net/socket.c:2501 ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555 __sys_sendmsg net/socket.c:2584 [inline] __do_sys_sendmsg net/socket.c:2593 [inline] __se_sys_sendmsg net/socket.c:2591 [inline] __x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was stored to memory at: tun_get_link_ksettings+0x37/0x60 drivers/net/tun.c:3544 __ethtool_get_link_ksettings+0x17b/0x260 net/ethtool/ioctl.c:441 ethnl_set_linkmodes+0xee/0x19d0 net/ethtool/linkmodes.c:327 ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640 genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline] genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065 netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577 genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg net/socket.c:747 [inline] ____sys_sendmsg+0xa24/0xe40 net/socket.c:2501 ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555 __sys_sendmsg net/socket.c:2584 [inline] __do_sys_sendmsg net/socket.c:2593 [inline] __se_sys_sendmsg net/socket.c:2591 [inline] __x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was stored to memory at: tun_set_link_ksettings+0x37/0x60 drivers/net/tun.c:3553 ethtool_set_link_ksettings+0x600/0x690 net/ethtool/ioctl.c:609 __dev_ethtool net/ethtool/ioctl.c:3024 [inline] dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078 dev_ioctl+0xb07/0x1270 net/core/dev_ioctl.c:524 sock_do_ioctl+0x295/0x540 net/socket.c:1213 sock_i ---truncated--- | |
| Title | ethtool: Fix uninitialized number of lanes | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-12-09T00:00:54.769Z
Reserved: 2025-12-08T23:58:35.275Z
Link: CVE-2023-53798
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2025-12-09T01:16:51.470
Modified: 2025-12-09T18:37:13.640
Link: CVE-2023-53798
Redhat
OpenCVE Enrichment
No data.
Weaknesses
No weakness.