CVE-2025-71091: team: fix check for port enabled in team_queue_override_port_prio_changed()

Vulnerability summary

CVE-2025-71091 is a high (CVSS 7.8) Use After Free vulnerability in linux. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 3.7% of scored vulnerabilities.

Timeline

1. 13-01-2026
   PublishedVulnerability first disclosed.
2. 19-10-2026
   Last modifiedVulnerability information updated.

Description

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 ]------------ 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-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.