linux — security advisory
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 [inli
- Products
- linux
- Affected versions
- 6.1.27-1
- Fixed versions
- 6.1.37-1, 6.3.7-1
- CVEs
- CVE-2023-53798
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 15:10 UTC · Revision 1
Source evidence
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 [inli
osv:DEBIAN-CVE-2023-53798
linux
Fixed versions: 6.1.37-1
linux
Fixed versions: 6.3.7-1
linux
Fixed versions: 6.3.7-1
Complete source record
{
"id": "c75420945bcd2822bae55e807cbf7cccbc2d19cd915d239e21ecebc691b2f60d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-53798",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-53798",
"summary": "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 [inli",
"evidence": "osv:DEBIAN-CVE-2023-53798",
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{
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"aliases": [
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"ecosystem": "Debian:12"
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"package": {
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],
"modified": "2026-10-26T17:47:30.144187108Z",
"provider": "osv",
"upstream": [
"CVE-2023-53798"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-53798"
]
},
"related_cves": [
{
"value": "CVE-2023-53798",
"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 454638,
"published_at": "2025-12-09T01:16:51.47+00:00"
}