CVE-2024-46857

net/mlx5: Fix bridge mode operations when there are no VFs

Published Sep 27, 2024 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix bridge mode operations when there are no VFs

Currently, trying to set the bridge mode attribute when numvfs=0 leads to a
crash:

bridge link set dev eth2 hwmode vepa

[ 168.967392] BUG: kernel NULL pointer dereference, address: 0000000000000030
[...]
[ 168.969989] RIP: 0010:mlx5_add_flow_rules+0x1f/0x300 [mlx5_core]
[...]
[ 168.976037] Call Trace:
[ 168.976188] <TASK>
[ 168.978620] _mlx5_eswitch_set_vepa_locked+0x113/0x230 [mlx5_core]
[ 168.979074] mlx5_eswitch_set_vepa+0x7f/0xa0 [mlx5_core]
[ 168.979471] rtnl_bridge_setlink+0xe9/0x1f0
[ 168.979714] rtnetlink_rcv_msg+0x159/0x400
[ 168.980451] netlink_rcv_skb+0x54/0x100
[ 168.980675] netlink_unicast+0x241/0x360
[ 168.980918] netlink_sendmsg+0x1f6/0x430
[ 168.981162] ____sys_sendmsg+0x3bb/0x3f0
[ 168.982155] ___sys_sendmsg+0x88/0xd0
[ 168.985036] __sys_sendmsg+0x59/0xa0
[ 168.985477] do_syscall_64+0x79/0x150
[ 168.987273] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 168.987773] RIP: 0033:0x7f8f7950f917

(esw->fdb_table.legacy.vepa_fdb is null)

The bridge mode is only relevant when there are multiple functions per
port. Therefore, prevent setting and getting this setting when there are no
VFs.

Note that after this change, there are no settings to change on the PF
interface using `bridge link` when there are no VFs, so the interface no
longer appears in the `bridge link` output.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4008-1 linux-6.1 security update
Debian DSA Debian DSA DSA-5782-1 linux security update
Ubuntu USN Ubuntu USN USN-7154-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7155-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-7156-1 Linux kernel (GKE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7154-2 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7196-1 Linux kernel (Azure) vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:2.3:o:linux:linux_kernel:6.11:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.11:rc7:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-476
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix bridge mode operations when there are no VFs Currently, trying to set the bridge mode attribute when numvfs=0 leads to a crash: bridge link set dev eth2 hwmode vepa [ 168.967392] BUG: kernel NULL pointer dereference, address: 0000000000000030 [...] [ 168.969989] RIP: 0010:mlx5_add_flow_rules+0x1f/0x300 [mlx5_core] [...] [ 168.976037] Call Trace: [ 168.976188] <TASK> [ 168.978620] _mlx5_eswitch_set_vepa_locked+0x113/0x230 [mlx5_core] [ 168.979074] mlx5_eswitch_set_vepa+0x7f/0xa0 [mlx5_core] [ 168.979471] rtnl_bridge_setlink+0xe9/0x1f0 [ 168.979714] rtnetlink_rcv_msg+0x159/0x400 [ 168.980451] netlink_rcv_skb+0x54/0x100 [ 168.980675] netlink_unicast+0x241/0x360 [ 168.980918] netlink_sendmsg+0x1f6/0x430 [ 168.981162] ____sys_sendmsg+0x3bb/0x3f0 [ 168.982155] ___sys_sendmsg+0x88/0xd0 [ 168.985036] __sys_sendmsg+0x59/0xa0 [ 168.985477] do_syscall_64+0x79/0x150 [ 168.987273] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 168.987773] RIP: 0033:0x7f8f7950f917 (esw->fdb_table.legacy.vepa_fdb is null) The bridge mode is only relevant when there are multiple functions per port. Therefore, prevent setting and getting this setting when there are no VFs. Note that after this change, there are no settings to change on the PF interface using `bridge link` when there are no VFs, so the interface no longer appears in the `bridge link` output.
Title net/mlx5: Fix bridge mode operations when there are no VFs
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 8:37 PM
Reserved
Sep 11, 2024, 3:12 PM
Status
Modified
Published
Sep 27, 2024, 1:15 PM
Modified
Jun 17, 2026, 7:56 AM
Severity
Moderate
Public date
Sep 27, 2024, 12:00 AM