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Linux KernelOperating system · Linux

CVE-2023-53103

MEDIUM · 5.5 CVSS v3.1 Published 2025-05-02
Fix available
A fix is available. Upgrade to 5.15.104 / 6.1.21 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: bonding: restore bond's IFF_SLAVE flag if a non-eth dev enslave fails syzbot reported a warning[1] where the bond device itself is a slave and we try to enslave a non-ethernet device as the first slave which fails but then in the error path when ether_setup() restores the bond device it also clears all flags. In my previous fix[2] I restored the IFF_MASTER flag, but I didn't consider the case that the bond device itself might also be a slave with IFF_SLAVE set, so we need to restore that flag as well. Use the bond_ether_setup helper which does the right thing and restores the bond's flags properly. Steps to reproduce using a nlmon dev: $ ip l add nlmon0 type nlmon $ ip l add bond1 type bond $ ip l add bond2 type bond $ ip l set bond1 master bond2 $ ip l set dev nlmon0 master bond1 $ ip -d l sh dev bond1 22: bond1: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noqueue master bond2 state DOWN mode DEFAULT group default qlen 1000 (now bond1's IFF_SLAVE flag is gone and we'll hit a warning[3] if we try to delete it) [1] https://syzkaller.appspot.com/bug?id=391c7b1f6522182899efba27d891f1743e8eb3ef [2] commit 7d5cd2ce5292 ("bonding: correctly handle bonding type change on enslave failure") [3] example warning: [ 27.008664] bond1: (slave nlmon0): The slave device specified does not support setting the MAC address [ 27.008692] bond1: (slave nlmon0): Error -95 calling set_mac_address [ 32.464639] bond1 (unregistering): Released all slaves [ 32.464685] ------------[ cut here ]------------ [ 32.464686] WARNING: CPU: 1 PID: 2004 at net/core/dev.c:10829 unregister_netdevice_many+0x72a/0x780 [ 32.464694] Modules linked in: br_netfilter bridge bonding virtio_net [ 32.464699] CPU: 1 PID: 2004 Comm: ip Kdump: loaded Not tainted 5.18.0-rc3+ #47 [ 32.464703] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.1-2.fc37 04/01/2014 [ 32.464704] RIP: 0010:unregister_netdevice_many+0x72a/0x780 [ 32.464707] Code: 99 fd ff ff ba 90 1a 00 00 48 c7 c6 f4 02 66 96 48 c7 c7 20 4d 35 96 c6 05 fa c7 2b 02 01 e8 be 6f 4a 00 0f 0b e9 73 fd ff ff <0f> 0b e9 5f fd ff ff 80 3d e3 c7 2b 02 00 0f 85 3b fd ff ff ba 59 [ 32.464710] RSP: 0018:ffffa006422d7820 EFLAGS: 00010206 [ 32.464712] RAX: ffff8f6e077140a0 RBX: ffffa006422d7888 RCX: 0000000000000000 [ 32.464714] RDX: ffff8f6e12edbe58 RSI: 0000000000000296 RDI: ffffffff96d4a520 [ 32.464716] RBP: ffff8f6e07714000 R08: ffffffff96d63600 R09: ffffa006422d7728 [ 32.464717] R10: 0000000000000ec0 R11: ffffffff9698c988 R12: ffff8f6e12edb140 [ 32.464719] R13: dead000000000122 R14: dead000000000100 R15: ffff8f6e12edb140 [ 32.464723] FS: 00007f297c2f1740(0000) GS:ffff8f6e5d900000(0000) knlGS:0000000000000000 [ 32.464725] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 32.464726] CR2: 00007f297bf1c800 CR3: 00000000115e8000 CR4: 0000000000350ee0 [ 32.464730] Call Trace: [ 32.464763] <TASK> [ 32.464767] rtnl_dellink+0x13e/0x380 [ 32.464776] ? cred_has_capability.isra.0+0x68/0x100 [ 32.464780] ? __rtnl_unlock+0x33/0x60 [ 32.464783] ? bpf_lsm_capset+0x10/0x10 [ 32.464786] ? security_capable+0x36/0x50 [ 32.464790] rtnetlink_rcv_msg+0x14e/0x3b0 [ 32.464792] ? _copy_to_iter+0xb1/0x790 [ 32.464796] ? post_alloc_hook+0xa0/0x160 [ 32.464799] ? rtnl_calcit.isra.0+0x110/0x110 [ 32.464802] netlink_rcv_skb+0x50/0xf0 [ 32.464806] netlink_unicast+0x216/0x340 [ 32.464809] netlink_sendmsg+0x23f/0x480 [ 32.464812] sock_sendmsg+0x5e/0x60 [ 32.464815] ____sys_sendmsg+0x22c/0x270 [ 32.464818] ? import_iovec+0x17/0x20 [ 32.464821] ? sendmsg_copy_msghdr+0x59/0x90 [ 32.464823] ? do_set_pte+0xa0/0xe0 [ 32.464828] ___sys_sendmsg+0x81/0xc0 [ 32.464832] ? mod_objcg_state+0xc6/0x300 [ 32.464835] ? refill_obj_stock+0xa9/0x160 [ 32.464838] ? memcg_slab_free_hook+0x1a5/0x1f0 [ 32.464842] __sys_sendm ---truncated---

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.2.1, < 5.15.104>= 5.16, < 6.1.21>= 6.2, < 6.2.8= 4.2= 6.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.15.104 / 6.1.21 / 6.2.8 or later
Fixed in 5.15.1046.1.216.2.8
Vendor patch git.kernel.org →
Recommended fix High confidence

5.15.104+ or 6.1.21+ or 6.2.8+ (choose the latest stable kernel in your kernel series)

  1. Upgrade the Linux kernel to one of the following fixed versions: 5.15.104 or later in the 5.15.x series, 6.1.21 or later in the 6.1.x series, or 6.2.8 or later in the 6.2.x series
  2. After upgrading, reboot the system to load the fixed kernel
  3. Verify the fix by attempting the reproduction steps: create an nlmon device, create two bond devices, set one bond as master of the other, then attempt to enslave the nlmon device - this should no longer cause the IFF_SLAVE flag to be incorrectly cleared from the bond device
Caveat Kernel upgrades may require matching kernel module recompilation; ensure all proprietary drivers are compatible with the new kernel version before upgrading in production environments

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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