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

net/mlx5e: xsk: Fix unlocked writing to ICOSQ

During napi poll, when the affinity changes and there's still XSK work
to be done, we trigger an ICOSQ interrupt on the new CPU. However, this
triggering on the ICOSQ is done unprotected.

There are 2 such races:

A) mlx5e_trigger_irq() is called while mlx5e_xsk_alloc_rx_mpwqe() is
running from a different CPU due to affinity change. This can happen
because IRQ triggering is done after napi_complete_done(). At this point
the NAPI can be scheduled on a different CPU. Like this:

CPU A (old affinity, NAPI tail) CPU B (new affinity, fresh NAPI)
------------------------------- --------------------------------
napi_complete_done() clears SCHED
mlx5e_cq_arm(...)
napi_schedule_prep() sets SCHED
mlx5e_napi_poll()
mlx5e_xsk_alloc_rx_mpwqe()
mlx5e_icosq_sync_lock() // noop
memcpy 640 B UMR body
advance sq->pc by 10
mlx5e_trigger_irq(&c->icosq)
wqe_info[pi] = {NOP, 1}
mlx5e_post_nop() advances sq->pc

B) mlx5e_trigger_irq() is called on the ICOSQ when
mlx5e_trigger_napi_icosq() is running.

The obvious fix would be to lock the ICOSQ. But ICOSQ has an optimized
locking scheme that doesn't work for this scenario. Kick the async ICOSQ
instead which is always locked.

This issue was noticed in the wild with the following splat:

netdevice: ge-0-0-1: Bad OP in ICOSQ CQE: 0xd
WARNING: drivers/net/ethernet/mellanox/mlx5/core/en_rx.c:826 [...]
[...]
Call Trace:
<IRQ>
mlx5e_napi_poll+0x11d/0x7f0 [mlx5_core]
__napi_poll+0x30/0x200
? skb_defer_free_flush+0x9c/0xc0
net_rx_action+0x2fe/0x3f0
handle_softirqs+0xd8/0x340
__irq_exit_rcu+0xbc/0xe0
common_interrupt+0x85/0xa0
</IRQ>
<TASK>
asm_common_interrupt+0x26/0x40
[...]
---[ end trace 0000000000000000 ]---
mlx5_core 0000:08:00.0 ge-0-0-1: Error cqe on cqn 0x548, ci 0x2022, qn 0x8f4,
opcode 0xd, syndrome 0x2, vendor syndrome 0x68
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000030: 00 00 00 00 01 00 68 02 01 00 08 f4 de 14 59 d2
WQE DUMP: WQ size 16384 WQ cur size 0, WQE index 0x1e14, len: 64
00000000: 00 00 00 01 d9 ed 80 02 00 00 00 01 d9 ed 90 02
00000010: 00 00 00 01 d9 ed a0 02 00 00 00 01 d9 ed b0 02
00000020: 00 00 00 01 d9 ed c0 02 00 00 00 01 d9 ed d0 02
00000030: 00 00 00 01 d9 ed e0 02 00 00 00 01 d9 ed f0 02
mlx5_core 0000:08:00.0 ge-0-0-1: Error cqe on cqn 0x548, ci 0x2023, qn 0x8f4,
opcode 0xd, syndrome 0x5, vendor syndrome 0xf9
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000030: 00 00 00 00 01 00 f9 05 01 00 08 f4 de 15 cf d2
Published: 2026-07-24
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability involves an unprotected write to the ICOSQ data structure during NAPI polling when CPU affinity changes occur. This race condition can trigger an interrupt that advances the queue pointer without proper synchronization, leading to corrupted data and erroneous completion queue entries. The result can manifest as a kernel panic or system hang, thereby compromising availability.

Affected Systems

All Linux kernel installations that include the mlx5e driver are affected. The issue is present in kernel versions that use the older icosq implementation before the patch that introduces proper locking or asynchronous sprouting was applied.

Risk and Exploitability

The risk is considered low based on an EPSS score of less than 1% and the fact that the vulnerability is not listed in the CISA KEV catalog. Exploitation would require a local privilege or kernel context, as the race occurs within kernel networking code. While a successful race could crash the system or cause a denial of service, there is no evidence of an active exploit in the wild. The fix was addressed in the kernel community after observing kernel warnings and errors documented in the relevant SPLAT traces.

Generated by OpenCVE AI on August 13, 2026 at 12:32 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply kernel update that includes the ICOSQ race condition fix; this vulnerability corresponds to CWE-820 and requires proper synchronization to prevent data corruption.
  • If using a distro‑ or vendorized kernel, install the vendor's security update that includes that fix.
  • After upgrading, restart network interfaces or reboot the system to reinitialize the mlx5e driver and verify that ICOSQ warnings no longer appear in system logs.

Generated by OpenCVE AI on August 13, 2026 at 12:32 UTC.

Tracking

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Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8618-1 Linux kernel vulnerabilities
History

Tue, 11 Aug 2026 18:45:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*

Mon, 03 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Wed, 29 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-820
References
Metrics threat_severity

None

 threat_severity

Moderate

Tue, 28 Jul 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Mon, 27 Jul 2026 05:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Fri, 24 Jul 2026 18:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: xsk: Fix unlocked writing to ICOSQ During napi poll, when the affinity changes and there's still XSK work to be done, we trigger an ICOSQ interrupt on the new CPU. However, this triggering on the ICOSQ is done unprotected. There are 2 such races: A) mlx5e_trigger_irq() is called while mlx5e_xsk_alloc_rx_mpwqe() is running from a different CPU due to affinity change. This can happen because IRQ triggering is done after napi_complete_done(). At this point the NAPI can be scheduled on a different CPU. Like this: CPU A (old affinity, NAPI tail) CPU B (new affinity, fresh NAPI) ------------------------------- -------------------------------- napi_complete_done() clears SCHED mlx5e_cq_arm(...) napi_schedule_prep() sets SCHED mlx5e_napi_poll() mlx5e_xsk_alloc_rx_mpwqe() mlx5e_icosq_sync_lock() // noop memcpy 640 B UMR body advance sq->pc by 10 mlx5e_trigger_irq(&c->icosq) wqe_info[pi] = {NOP, 1} mlx5e_post_nop() advances sq->pc B) mlx5e_trigger_irq() is called on the ICOSQ when mlx5e_trigger_napi_icosq() is running. The obvious fix would be to lock the ICOSQ. But ICOSQ has an optimized locking scheme that doesn't work for this scenario. Kick the async ICOSQ instead which is always locked. This issue was noticed in the wild with the following splat: netdevice: ge-0-0-1: Bad OP in ICOSQ CQE: 0xd WARNING: drivers/net/ethernet/mellanox/mlx5/core/en_rx.c:826 [...] [...] Call Trace: <IRQ> mlx5e_napi_poll+0x11d/0x7f0 [mlx5_core] __napi_poll+0x30/0x200 ? skb_defer_free_flush+0x9c/0xc0 net_rx_action+0x2fe/0x3f0 handle_softirqs+0xd8/0x340 __irq_exit_rcu+0xbc/0xe0 common_interrupt+0x85/0xa0 </IRQ> <TASK> asm_common_interrupt+0x26/0x40 [...] ---[ end trace 0000000000000000 ]--- mlx5_core 0000:08:00.0 ge-0-0-1: Error cqe on cqn 0x548, ci 0x2022, qn 0x8f4, opcode 0xd, syndrome 0x2, vendor syndrome 0x68 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000030: 00 00 00 00 01 00 68 02 01 00 08 f4 de 14 59 d2 WQE DUMP: WQ size 16384 WQ cur size 0, WQE index 0x1e14, len: 64 00000000: 00 00 00 01 d9 ed 80 02 00 00 00 01 d9 ed 90 02 00000010: 00 00 00 01 d9 ed a0 02 00 00 00 01 d9 ed b0 02 00000020: 00 00 00 01 d9 ed c0 02 00 00 00 01 d9 ed d0 02 00000030: 00 00 00 01 d9 ed e0 02 00 00 00 01 d9 ed f0 02 mlx5_core 0000:08:00.0 ge-0-0-1: Error cqe on cqn 0x548, ci 0x2023, qn 0x8f4, opcode 0xd, syndrome 0x5, vendor syndrome 0xf9 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00000030: 00 00 00 00 01 00 f9 05 01 00 08 f4 de 15 cf d2
Title net/mlx5e: xsk: Fix unlocked writing to ICOSQ
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-05T12:40:03.069Z

Reserved: 2026-07-19T15:36:31.769Z

Link: CVE-2026-64210

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-07-24T16:16:48.623

Modified: 2026-08-11T18:27:00.957

Link: CVE-2026-64210

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-24T00:00:00Z

Links: CVE-2026-64210 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-13T12:45:03Z

Weaknesses