Bug 2492728 (CVE-2026-53230)

Summary:	CVE-2026-53230 kernel: net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's mlx5 driver. The mlx5_query_nic_vport_mac_list function, which handles querying network interface card (NIC) virtual port (vport) MAC addresses, incorrectly sizes its internal buffer. When a Virtual Function (VF) vport is queried with a larger configured maximum, the firmware response can overflow this buffer. This leads to a memory corruption issue, specifically a slab-out-of-bounds error, which could potentially be exploited by an attacker to cause a denial of service or other system instability.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-06-25 10:02:39 UTC

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list

mlx5_query_nic_vport_mac_list() sizes its firmware command buffer using
the PF's log_max_current_uc/mc_list capabilities. When querying a VF
vport with a larger configured max (via devlink), the firmware response
can overflow this buffer:

 BUG: KASAN: slab-out-of-bounds in mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]
 Read of size 4 at addr ff1100013ffc8a12 by task kworker/u96:2/385

 CPU: 12 UID: 0 PID: 385 Comm: kworker/u96:2 Not tainted 7.0.0-rc6+ #1 PREEMPT
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
 Workqueue: mlx5_esw_wq esw_vport_change_handler [mlx5_core]
 Call Trace:
  <TASK>
  dump_stack_lvl+0x69/0xa0
  print_report+0x176/0x4e4
  kasan_report+0xc8/0x100
  mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]
  esw_update_vport_addr_list+0x2e3/0xda0 [mlx5_core]
  esw_vport_change_handle_locked+0xa1f/0x1060 [mlx5_core]
  esw_vport_change_handler+0x6a/0x90 [mlx5_core]
  process_one_work+0x87f/0x15e0
  worker_thread+0x62b/0x1020
  kthread+0x375/0x490
  ret_from_fork+0x4dc/0x810
  ret_from_fork_asm+0x11/0x20
  </TASK>

Fix by querying the vport's own HCA caps to size the buffer correctly.
Refactor the function to allocate and return the MAC list internally,
removing the caller's dependency on knowing the correct max.

Comment 1 Keith Grant 2026-06-25 21:52:14 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062508-CVE-2026-53230-ddd6@gregkh/T