CVE-2025-71091
Published: 13 January 2026
Summary
CVE-2025-71091 is a high-severity an unspecified weakness vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 1.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 CM-7 (Least Functionality) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-71091 is a vulnerability in the Linux kernel's team networking driver, specifically within the function team_queue_override_port_prio_changed() in drivers/net/team/team_core.c. The issue causes a list_del corruption when a port is disabled after being enabled with a non-zero queue_id, leading to an attempt to remove an already-deleted entry from the qom_list. This triggers a kernel BUG at lib/list_debug.c:59, resulting in an Oops with invalid opcode. The vulnerability was identified through a syzkaller fuzzing trace and carries a CVSS v3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
A local attacker with low privileges (PR:L) can exploit this vulnerability by sending crafted netlink messages via the generic netlink interface, targeting team_nl_options_set_doit() and the team_priority_option_set() path. This involves enabling a port with queue_id != 0, disabling it (which removes it from the list), and then changing its priority, bypassing an inadequate check and invoking __team_queue_override_port_del() on a stale list entry. Successful exploitation can cause a kernel panic, denial of service, or potentially lead to high-impact confidentiality, integrity, and availability violations, such as arbitrary code execution in kernel context.
Mitigation requires applying upstream patches from the Linux kernel stable repository, as detailed in the referenced commits: https://git.kernel.org/stable/c/107d245f84cb4f55f597d31eda34b42a2b7d6952, https://git.kernel.org/stable/c/25029e813c4aae5fcf7118e8dd5c56e382b9a1a3, https://git.kernel.org/stable/c/53a727a8bfd78c739e130a781192d0f6f8e03d39, https://git.kernel.org/stable/c/6bfb62b6010a16112dcae52f490e5e0e6abe12a3, and https://git.kernel.org/stable/c/932ac51d9953eaf77a1252f79b656d4ca86163c6. The fix modifies team_queue_override_port_prio_changed() to return early if the port is not enabled, preventing the invalid list operation.
The vulnerability was discovered via syzkaller fuzzing and has no reported real-world exploitation as of publication on 2026-01-13.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2256
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: team: fix check for port enabled in team_queue_override_port_prio_changed() There has been a syzkaller bug reported recently with the following trace: list_del corruption, ffff888058bea080->prev is LIST_POISON2 (dead000000000122) ------------[ cut here ]------------…
more
kernel BUG at lib/list_debug.c:59! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 3 UID: 0 PID: 21246 Comm: syz.0.2928 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:__list_del_entry_valid_or_report+0x13e/0x200 lib/list_debug.c:59 Code: 48 c7 c7 e0 71 f0 8b e8 30 08 ef fc 90 0f 0b 48 89 ef e8 a5 02 55 fd 48 89 ea 48 89 de 48 c7 c7 40 72 f0 8b e8 13 08 ef fc 90 <0f> 0b 48 89 ef e8 88 02 55 fd 48 89 ea 48 b8 00 00 00 00 00 fc ff RSP: 0018:ffffc9000d49f370 EFLAGS: 00010286 RAX: 000000000000004e RBX: ffff888058bea080 RCX: ffffc9002817d000 RDX: 0000000000000000 RSI: ffffffff819becc6 RDI: 0000000000000005 RBP: dead000000000122 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000080000000 R11: 0000000000000001 R12: ffff888039e9c230 R13: ffff888058bea088 R14: ffff888058bea080 R15: ffff888055461480 FS: 00007fbbcfe6f6c0(0000) GS:ffff8880d6d0a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3afcb0 CR3: 00000000382c7000 CR4: 0000000000352ef0 Call Trace: <TASK> __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:223 [inline] list_del_rcu include/linux/rculist.h:178 [inline] __team_queue_override_port_del drivers/net/team/team_core.c:826 [inline] __team_queue_override_port_del drivers/net/team/team_core.c:821 [inline] team_queue_override_port_prio_changed drivers/net/team/team_core.c:883 [inline] team_priority_option_set+0x171/0x2f0 drivers/net/team/team_core.c:1534 team_option_set drivers/net/team/team_core.c:376 [inline] team_nl_options_set_doit+0x8ae/0xe60 drivers/net/team/team_core.c:2653 genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa98/0xc70 net/socket.c:2630 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2684 __sys_sendmsg+0x16d/0x220 net/socket.c:2716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The problem is in this flow: 1) Port is enabled, queue_id != 0, in qom_list 2) Port gets disabled -> team_port_disable() -> team_queue_override_port_del() -> del (removed from list) 3) Port is disabled, queue_id != 0, not in any list 4) Priority changes -> team_queue_override_port_prio_changed() -> checks: port disabled && queue_id != 0 -> calls del - hits the BUG as it is removed already To fix this, change the check in team_queue_override_port_prio_changed() so it returns early if port is not enabled.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel vulnerability directly enables privilege escalation via crafted netlink input (T1068) and endpoint DoS via list corruption leading to panic (T1499.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates CVE-2025-71091 by requiring timely remediation of the kernel flaw through application of upstream patches that fix the inadequate port enabled check in team_queue_override_port_prio_changed().
Prevents exploitation by configuring systems to disable the non-essential team networking driver, avoiding loading of the vulnerable code path in drivers/net/team/team_core.c.
Provides kernel memory protections such as list debugging and use-after-free mitigations that limit the impact of the list_del corruption triggered by crafted netlink messages.