# CVE-2023-53811: RDMA/irdma: Cap MSIX used to online CPUs + 1

> A flaw in the Linux kernel irdma driver allows a local attacker to trigger a kernel warning and potential denial of service by exceeding MSIX vector limits.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-53811, DEBIAN-CVE-2023-53811, GHSA-4q86-c76w-9mx5, UBUNTU-CVE-2023-53811

## What is CVE-2023-53811?

CVE-2023-53811 is a denial of service vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

RDMA/irdma: Cap MSIX used to online CPUs + 1

The irdma driver can use a maximum number of msix vectors equal
to num_online_cpus() + 1 and the kernel warning stack below is shown
if that number is exceeded.

The kernel throws a warning as the driver tries to update the affinity
hint with a CPU mask greater than the max CPU IDs. Fix this by capping
the MSIX vectors to num_online_cpus() + 1.

 WARNING: CPU: 7 PID: 23655 at include/linux/cpumask.h:106 irdma_cfg_ceq_vector+0x34c/0x3f0 [irdma]
 RIP: 0010:irdma_cfg_ceq_vector+0x34c/0x3f0 [irdma]
 Call Trace:
 irdma_rt_init_hw+0xa62/0x1290 [irdma]
 ? irdma_alloc_local_mac_entry+0x1a0/0x1a0 [irdma]
 ? __is_kernel_percpu_address+0x63/0x310
 ? rcu_read_lock_held_common+0xe/0xb0
 ? irdma_lan_unregister_qset+0x280/0x280 [irdma]
 ? irdma_request_reset+0x80/0x80 [irdma]
 ? ice_get_qos_params+0x84/0x390 [ice]
 irdma_probe+0xa40/0xfc0 [irdma]
 ? rcu_read_lock_bh_held+0xd0/0xd0
 ? irdma_remove+0x140/0x140 [irdma]
 ? rcu_read_lock_sched_held+0x62/0xe0
 ? down_write+0x187/0x3d0
 ? auxiliary_match_id+0xf0/0x1a0
 ? irdma_remove+0x140/0x140 [irdma]
 auxiliary_bus_probe+0xa6/0x100
 __driver_probe_device+0x4a4/0xd50
 ? __device_attach_driver+0x2c0/0x2c0
 driver_probe_device+0x4a/0x110
 __driver_attach+0x1aa/0x350
 bus_for_each_dev+0x11d/0x1b0
 ? subsys_dev_iter_init+0xe0/0xe0
 bus_add_driver+0x3b1/0x610
 driver_register+0x18e/0x410
 ? 0xffffffffc0b88000
 irdma_init_module+0x50/0xaa [irdma]
 do_one_initcall+0x103/0x5f0
 ? perf_trace_initcall_level+0x420/0x420
 ? do_init_module+0x4e/0x700
 ? __kasan_kmalloc+0x7d/0xa0
 ? kmem_cache_alloc_trace+0x188/0x2b0
 ? kasan_unpoison+0x21/0x50
 do_init_module+0x1d1/0x700
 load_module+0x3867/0x5260
 ? layout_and_allocate+0x3990/0x3990
 ? rcu_read_lock_held_common+0xe/0xb0
 ? rcu_read_lock_sched_held+0x62/0xe0
 ? rcu_read_lock_bh_held+0xd0/0xd0
 ? __vmalloc_node_range+0x46b/0x890
 ? lock_release+0x5c8/0xba0
 ? alloc_vm_area+0x120/0x120
 ? selinux_kernel_module_from_file+0x2a5/0x300
 ? __inode_security_revalidate+0xf0/0xf0
 ? __do_sys_init_module+0x1db/0x260
 __do_sys_init_module+0x1db/0x260
 ? load_module+0x5260/0x5260
 ? do_syscall_64+0x22/0x450
 do_syscall_64+0xa5/0x450
 entry_SYSCALL_64_after_hwframe+0x66/0xdb

## Which versions are affected by CVE-2023-53811?


## How do I fix CVE-2023-53811?

Apply the vendor's patch.

## Is CVE-2023-53811 being exploited?

There is no known exploitation of CVE-2023-53811 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53811 and fix it if it is affected.

What it is: CVE-2023-53811 is a denial of service vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-53811 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-53811/ (Markdown: https://insights.sbomify.com/CVE-2023-53811/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53811
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53811
- OSV: https://osv.dev/vulnerability/CVE-2023-53811

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53811/
Summaries are generated and may contain mistakes; the official description above is the record.