CVE-2026-23099: bonding: limit BOND_MODE_8023AD to Ethernet devices
In the Linux kernel, the following vulnerability has been resolved:
bonding: limit BONDMODE8023AD to Ethernet devices
BONDMODE8023AD makes sense for ARPHRDETHER only.
syzbot reported:
BUG: KASAN: global-out-of-bounds in hwaddrcreate net/core/devaddrlists.c:63 [inline] BUG: KASAN: global-out-of-bounds in hwaddraddex+0x25d/0x760 net/core/devaddrlists.c:118 Read of size 16 at addr ffffffff8bf94040 by task syz.1.3580/19497
CPU: 1 UID: 0 PID: 19497 Comm: syz.1.3580 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: <TASK> dumpstacklvl+0xe8/0x150 lib/dumpstack.c:120 printaddressdescription mm/kasan/report.c:378 [inline] printreport+0xca/0x240 mm/kasan/report.c:482 kasanreport+0x118/0x150 mm/kasan/report.c:595 checkregioninline mm/kasan/generic.c:-1 [inline] kasancheckrange+0x2b0/0x2c0 mm/kasan/generic.c:200 asanmemcpy+0x29/0x70 mm/kasan/shadow.c:105 hwaddrcreate net/core/devaddrlists.c:63 [inline] hwaddraddex+0x25d/0x760 net/core/devaddrlists.c:118 devmcadd net/core/devaddrlists.c:868 [inline] devmcadd+0xa1/0x120 net/core/devaddrlists.c:886 bondenslave+0x2b8b/0x3ac0 drivers/net/bonding/bondmain.c:2180 dosetmaster+0x533/0x6d0 net/core/rtnetlink.c:2963 dosetlink+0xcf0/0x41c0 net/core/rtnetlink.c:3165 rtnlchangelink net/core/rtnetlink.c:3776 [inline] rtnlnewlink net/core/rtnetlink.c:3935 [inline] rtnlnewlink+0x161c/0x1c90 net/core/rtnetlink.c:4072 rtnetlinkrcvmsg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlinkrcvskb+0x208/0x470 net/netlink/afnetlink.c:2550 netlinkunicastkernel net/netlink/afnetlink.c:1318 [inline] netlinkunicast+0x82f/0x9e0 net/netlink/afnetlink.c:1344 netlinksendmsg+0x805/0xb30 net/netlink/afnetlink.c:1894 socksendmsgnosec net/socket.c:727 [inline] socksendmsg+0x21c/0x270 net/socket.c:742 syssendmsg+0x505/0x820 net/socket.c:2592 syssendmsg+0x21f/0x2a0 net/socket.c:2646 syssendmsg+0x164/0x220 net/socket.c:2678 dosyscall32irqson arch/x86/entry/syscall32.c:83 [inline] dofastsyscall32+0x1dc/0x560 arch/x86/entry/syscall32.c:307 dofastsyscall32+0x34/0x80 arch/x86/entry/syscall32.c:332 entrySYSENTERcompatafterhwframe+0x84/0x8e </TASK>
The buggy address belongs to the variable: lacpdumcastaddr+0x0/0x40
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Ensure BOND_MODE_8023AD is only applied to Ethernet devices (ARPHRD_ETHER). Do not configure or enable BOND_MODE_8023AD on non-Ethernet interfaces (any interface whose ARPHRD type is not ARPHRD_ETHER).
Linux kernel bonding BOND_MODE_8023AD usage = ARPHRD_ETHER only - Operational
Audit existing bonding configurations and enslaved interfaces; for any bonded interface that is using BOND_MODE_8023AD on a non-Ethernet device, remove the non-Ethernet device from the bond or change the bond mode to one supported by that device. Repeat checks after configuration changes to confirm no non-Ethernet devices are assigned BOND_MODE_8023AD.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23099?
CVE-2026-23099 has been categorized with a severity level that may affect the stability of network bonding in Linux systems.
How do I fix CVE-2026-23099?
To fix CVE-2026-23099, ensure that your system is updated to the latest version of the Linux kernel that addresses this vulnerability.
What systems are affected by CVE-2026-23099?
CVE-2026-23099 affects systems running Linux kernel versions that utilize BOND_MODE_8023AD for bonding Ethernet devices.
What does CVE-2026-23099 impact?
CVE-2026-23099 impacts the functionality of bonding modes in Linux, particularly restricting BOND_MODE_8023AD to Ethernet devices only.
Is CVE-2026-23099 a remote exploit vulnerability?
CVE-2026-23099 is not categorized as a remote exploit vulnerability, but rather a local configuration issue in network bonding.