--- id: CVE-2025-23163 title: 'net: vlan: don''t propagate flags on open' summary: |- In the Linux kernel, the following vulnerability has been resolved: net: vlan: don't propagate flags on open With the device instance lock, there is now a possibility of a deadlock: [ 1.211455] =====================================… severity: none vendor: Linux product: Linux affected: - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < a32f1d4f1f4c9d978698f3c718621f6198f2e7ac - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < b1e3eeb037256a2f1206a8d69810ec47eb152026 - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 523fa0979d842443aa14b80002e45b471cbac137 - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 53fb25e90c0a503a17c639341ba5e755cb2feb5c - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < d537859e56bcc3091805c524484a4c85386b3cc8 - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 299d7d27af6b5844cda06a0fdfa635705e1bc50f - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 8980018a9806743d9b80837330d46f06ecf78516 - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 538b43aa21e3b17c110104efd218b966d2eda5f8 - >- Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 27b918007d96402aba10ed52a6af8015230f1793 - Linux 2.6.23 ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2026-11-05T20:40:06.955013Z' published: '2025-05-01' updated: '2026-11-05' sourceUpdated: '2026-11-05T20:41:52.928Z' source: CVEORG sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-23163' references: - url: 'https://git.kernel.org/stable/c/a32f1d4f1f4c9d978698f3c718621f6198f2e7ac' - url: 'https://git.kernel.org/stable/c/b1e3eeb037256a2f1206a8d69810ec47eb152026' - url: 'https://git.kernel.org/stable/c/523fa0979d842443aa14b80002e45b471cbac137' - url: 'https://git.kernel.org/stable/c/53fb25e90c0a503a17c639341ba5e755cb2feb5c' - url: 'https://git.kernel.org/stable/c/d537859e56bcc3091805c524484a4c85386b3cc8' - url: 'https://git.kernel.org/stable/c/299d7d27af6b5844cda06a0fdfa635705e1bc50f' - url: 'https://git.kernel.org/stable/c/8980018a9806743d9b80837330d46f06ecf78516' - url: 'https://git.kernel.org/stable/c/538b43aa21e3b17c110104efd218b966d2eda5f8' - url: 'https://git.kernel.org/stable/c/27b918007d96402aba10ed52a6af8015230f1793' tags: - cve.org epss: 0.00156 epssPercentile: 0.04794 ingestedAt: '2026-11-05T22:38:31.868Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: net: vlan: don't propagate flags on open With the device instance lock, there is now a possibility of a deadlock: [ 1.211455] ============================================ [ 1.211571] WARNING: possible recursive locking detected [ 1.211687] 6.14.0-rc5-01215-g032756b4ca7a-dirty #5 Not tainted [ 1.211823] -------------------------------------------- [ 1.211936] ip/184 is trying to acquire lock: [ 1.212032] ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_set_allmulti+0x4e/0xb0 [ 1.212207] [ 1.212207] but task is already holding lock: [ 1.212332] ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x50/0xb0 [ 1.212487] [ 1.212487] other info that might help us debug this: [ 1.212626] Possible unsafe locking scenario: [ 1.212626] [ 1.212751] CPU0 [ 1.212815] ---- [ 1.212871] lock(&dev->lock); [ 1.212944] lock(&dev->lock); [ 1.213016] [ 1.213016] *** DEADLOCK *** [ 1.213016] [ 1.213143] May be due to missing lock nesting notation [ 1.213143] [ 1.213294] 3 locks held by ip/184: [ 1.213371] #0: ffffffff838b53e0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock+0x1b/0xa0 [ 1.213543] #1: ffffffff84e5fc70 (&net->rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock+0x37/0xa0 [ 1.213727] #2: ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x50/0xb0 [ 1.213895] [ 1.213895] stack backtrace: [ 1.213991] CPU: 0 UID: 0 PID: 184 Comm: ip Not tainted 6.14.0-rc5-01215-g032756b4ca7a-dirty #5 [ 1.213993] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [ 1.213994] Call Trace: [ 1.213995] [ 1.213996] dump_stack_lvl+0x8e/0xd0 [ 1.214000] print_deadlock_bug+0x28b/0x2a0 [ 1.214020] lock_acquire+0xea/0x2a0 [ 1.214027] __mutex_lock+0xbf/0xd40 [ 1.214038] dev_set_allmulti+0x4e/0xb0 # real_dev->flags & IFF_ALLMULTI [ 1.214040] vlan_dev_open+0xa5/0x170 # ndo_open on vlandev [ 1.214042] __dev_open+0x145/0x270 [ 1.214046] __dev_change_flags+0xb0/0x1e0 [ 1.214051] netif_change_flags+0x22/0x60 # IFF_UP vlandev [ 1.214053] dev_change_flags+0x61/0xb0 # for each device in group from dev->vlan_info [ 1.214055] vlan_device_event+0x766/0x7c0 # on netdevsim0 [ 1.214058] notifier_call_chain+0x78/0x120 [ 1.214062] netif_open+0x6d/0x90 [ 1.214064] dev_open+0x5b/0xb0 # locks netdevsim0 [ 1.214066] bond_enslave+0x64c/0x1230 [ 1.214075] do_set_master+0x175/0x1e0 # on netdevsim0 [ 1.214077] do_setlink+0x516/0x13b0 [ 1.214094] rtnl_newlink+0xaba/0xb80 [ 1.214132] rtnetlink_rcv_msg+0x440/0x490 [ 1.214144] netlink_rcv_skb+0xeb/0x120 [ 1.214150] netlink_unicast+0x1f9/0x320 [ 1.214153] netlink_sendmsg+0x346/0x3f0 [ 1.214157] __sock_sendmsg+0x86/0xb0 [ 1.214160] ____sys_sendmsg+0x1c8/0x220 [ 1.214164] ___sys_sendmsg+0x28f/0x2d0 [ 1.214179] __x64_sys_sendmsg+0xef/0x140 [ 1.214184] do_syscall_64+0xec/0x1d0 [ 1.214190] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 1.214191] RIP: 0033:0x7f2d1b4a7e56 Device setup: netdevsim0 (down) ^ ^ bond netdevsim1.100@netdevsim1 allmulticast=on (down) When we enslave the lower device (netdevsim0) which has a vlan, we propagate vlan's allmuti/promisc flags during ndo_open. This causes (re)locking on of the real_dev. Propagate allmulti/promisc on flags change, not on the open. There is a slight semantics change that vlans that are down now propagate the flags, but this seems unlikely to result in the real issues. Reproducer: echo 0 1 > /sys/bus/netdevsim/new_device dev_path=$(ls -d /sys/bus/netdevsim/devices/netdevsim0/net/*) dev=$(echo $dev_path | rev | cut -d/ -f1 | rev) ip link set dev $dev name netdevsim0 ip link set dev netdevsim0 up ip link add link netdevsim0 name netdevsim0.100 type vlan id 100 ip link set dev netdevsim0.100 allm ---truncated--- ## Affected - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < a32f1d4f1f4c9d978698f3c718621f6198f2e7ac` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < b1e3eeb037256a2f1206a8d69810ec47eb152026` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 523fa0979d842443aa14b80002e45b471cbac137` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 53fb25e90c0a503a17c639341ba5e755cb2feb5c` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < d537859e56bcc3091805c524484a4c85386b3cc8` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 299d7d27af6b5844cda06a0fdfa635705e1bc50f` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 8980018a9806743d9b80837330d46f06ecf78516` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 538b43aa21e3b17c110104efd218b966d2eda5f8` - `Linux >= 6c78dcbd47a68a7d25d2bee7a6c74b9136cb5fde < 27b918007d96402aba10ed52a6af8015230f1793` - `Linux 2.6.23` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.