CVE-2026-23099
Published: 04 February 2026
Summary
CVE-2026-23099 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 4.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel OOB read in bonding driver enables low-priv exploitation for privilege escalation via info leak or DoS.
NVD Description
In the Linux kernel, the following vulnerability has been resolved: bonding: limit BOND_MODE_8023AD to Ethernet devices BOND_MODE_8023AD makes sense for ARPHRD_ETHER only. syzbot reported: BUG: KASAN: global-out-of-bounds in __hw_addr_create net/core/dev_addr_lists.c:63 [inline] BUG: KASAN: global-out-of-bounds in __hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118 Read of size…
more
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> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105 __hw_addr_create net/core/dev_addr_lists.c:63 [inline] __hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118 __dev_mc_add net/core/dev_addr_lists.c:868 [inline] dev_mc_add+0xa1/0x120 net/core/dev_addr_lists.c:886 bond_enslave+0x2b8b/0x3ac0 drivers/net/bonding/bond_main.c:2180 do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2963 do_setlink+0xcf0/0x41c0 net/core/rtnetlink.c:3165 rtnl_changelink net/core/rtnetlink.c:3776 [inline] __rtnl_newlink net/core/rtnetlink.c:3935 [inline] rtnl_newlink+0x161c/0x1c90 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x820 net/socket.c:2592 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646 __sys_sendmsg+0x164/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x1dc/0x560 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e </TASK> The buggy address belongs to the variable: lacpdu_mcast_addr+0x0/0x40
Deeper analysisAI
CVE-2026-23099 is a memory safety vulnerability in the Linux kernel's bonding driver, specifically affecting the implementation of BOND_MODE_8023AD (LACP mode). The issue arises because the driver does not restrict this mode to Ethernet devices (ARPHRD_ETHER), allowing it to be applied to incompatible device types. This leads to a global-out-of-bounds read in the __hw_addr_add_ex function within net/core/dev_addr_lists.c, as detected by KASAN during the bond_enslave operation. The vulnerability was reported by syzbot via the syzkaller fuzzer.
A local attacker with low privileges can exploit this vulnerability by using rtnetlink to configure a bonding interface in 802.3ad mode and enslave a non-Ethernet device as a slave. This triggers the out-of-bounds memory access during multicast address addition for LACPdu, potentially resulting in information disclosure due to the read of 16 bytes beyond the lacpdu_mcast_addr bounds and system crashes from the kernel fault, as indicated by the CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H) with a base score of 7.1.
Mitigation is provided through kernel patches that explicitly limit BOND_MODE_8023AD to Ethernet devices only. Relevant stable kernel commits include 43dee6f7ef1d228821de1b61c292af3744c8d7da, 5063b2cd9b27d35ab788d707d7858ded0acc8f1d, 72925dbb0c8c7b16bf922e93c6cc03cbd8c955c4, 80c881e53a4fa0a80fa4bef7bc0ead0e8e88940d, and c84fcb79e5dbde0b8d5aeeaf04282d2149aebcf6, available in the Linux kernel git repository.
Details
- CWE(s)