Skip to content
Fencer Vulns
no cvss —

CVE-2023-53798 json

ethtool: Fix uninitialized number of lanes

published 2025-12-09 11 mo ago modified 2026-06-17 4 mo ago also EUVD-2023-60108

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

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 [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---

Patch / fix

  • Linux Linux 5.15.112, 6.1.29, 6.2.16, 6.3.3, 6.4
  • linux Debian 12 6.1.37-1
  • linux Debian 14, Debian 13 6.3.7-1

debian advisories DEBIAN-CVE-2023-53798

  • linux Ubuntu 22.04 LTS 5.15.0-83.92
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1044.49
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1041.49
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1041.46
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1037.40
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1041.46
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1046.53
  • linux-gkeop Ubuntu 22.04 LTS 5.15.0-1027.32

ubuntu advisories UBUNTU-CVE-2023-53798

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 8 4.18.0-553.el8_10
  • perf RHEL 8 4.18.0-553.el8_10
  • bpftool RHEL 8 4.18.0-553.el8_10
  • kernel-core RHEL 8 4.18.0-553.el8_10
  • kernel-tools RHEL 8 4.18.0-553.el8_10
  • python3-perf RHEL 8 4.18.0-553.el8_10
  • kernel-modules RHEL 8 4.18.0-553.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.el8_10

red hat advisories RHSA-2024:3138

  • kernel Rocky Linux 8 4.18.0-553.123.1.el8_10.cloud.0.1

rocky linux advisories RXSA-2024:3138

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-53798 updated cvss 5.5

kernel: ethtool: Fix uninitialized number of lanes

  • Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.el8_10, kernel 4.18.0-553.el8_10, bpftool 4.18.0-553.el8_10, kernel-core 4.18.0-553.el8_10, kernel-tools 4.18.0-553.el8_10, python3-perf 4.18.0-553.el8_10, +15 more Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.el8_10
    fixed: vendor fix RHSA-2024:3138
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.