# CVE-2024-47694: IB/mlx5: Fix UMR pd cleanup on error flow of driver init

> A null pointer dereference in the Linux kernel's mlx5 InfiniBand driver causes a system panic during driver initialization errors.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Oct 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-47694, GHSA-52mx-xj4w-gw54, UBUNTU-CVE-2024-47694

## What is CVE-2024-47694?

CVE-2024-47694 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. 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:

IB/mlx5: Fix UMR pd cleanup on error flow of driver init

The cited commit moves the pd allocation from function
mlx5r_umr_resource_cleanup() to a new function mlx5r_umr_cleanup().
So the fix in commit [1] is broken. In error flow, will hit panic [2].

Fix it by checking pd pointer to avoid panic if it is NULL;

[1] RDMA/mlx5: Fix UMR cleanup on error flow of driver init
[2]
 [  347.567063] infiniband mlx5_0: Couldn't register device with driver model
 [  347.591382] BUG: kernel NULL pointer dereference, address: 0000000000000020
 [  347.593438] #PF: supervisor read access in kernel mode
 [  347.595176] #PF: error_code(0x0000) - not-present page
 [  347.596962] PGD 0 P4D 0
 [  347.601361] RIP: 0010:ib_dealloc_pd_user+0x12/0xc0 [ib_core]
 [  347.604171] RSP: 0018:ffff888106293b10 EFLAGS: 00010282
 [  347.604834] RAX: 0000000000000000 RBX: 000000000000000e RCX: 0000000000000000
 [  347.605672] RDX: ffff888106293ad0 RSI: 0000000000000000 RDI: 0000000000000000
 [  347.606529] RBP: 0000000000000000 R08: ffff888106293ae0 R09: ffff888106293ae0
 [  347.607379] R10: 0000000000000a06 R11: 0000000000000000 R12: 0000000000000000
 [  347.608224] R13: ffffffffa0704dc0 R14: 0000000000000001 R15: 0000000000000001
 [  347.609067] FS:  00007fdc720cd9c0(0000) GS:ffff88852c880000(0000) knlGS:0000000000000000
 [  347.610094] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [  347.610727] CR2: 0000000000000020 CR3: 0000000103012003 CR4: 0000000000370eb0
 [  347.611421] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 [  347.612113] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 [  347.612804] Call Trace:
 [  347.613130]  <TASK>
 [  347.613417]  ? __die+0x20/0x60
 [  347.613793]  ? page_fault_oops+0x150/0x3e0
 [  347.614243]  ? free_msg+0x68/0x80 [mlx5_core]
 [  347.614840]  ? cmd_exec+0x48f/0x11d0 [mlx5_core]
 [  347.615359]  ? exc_page_fault+0x74/0x130
 [  347.615808]  ? asm_exc_page_fault+0x22/0x30
 [  347.616273]  ? ib_dealloc_pd_user+0x12/0xc0 [ib_core]
 [  347.616801]  mlx5r_umr_cleanup+0x23/0x90 [mlx5_ib]
 [  347.617365]  mlx5_ib_stage_pre_ib_reg_umr_cleanup+0x36/0x40 [mlx5_ib]
 [  347.618025]  __mlx5_ib_add+0x96/0xd0 [mlx5_ib]
 [  347.618539]  mlx5r_probe+0xe9/0x310 [mlx5_ib]
 [  347.619032]  ? kernfs_add_one+0x107/0x150
 [  347.619478]  ? __mlx5_ib_add+0xd0/0xd0 [mlx5_ib]
 [  347.619984]  auxiliary_bus_probe+0x3e/0x90
 [  347.620448]  really_probe+0xc5/0x3a0
 [  347.620857]  __driver_probe_device+0x80/0x160
 [  347.621325]  driver_probe_device+0x1e/0x90
 [  347.621770]  __driver_attach+0xec/0x1c0
 [  347.622213]  ? __device_attach_driver+0x100/0x100
 [  347.622724]  bus_for_each_dev+0x71/0xc0
 [  347.623151]  bus_add_driver+0xed/0x240
 [  347.623570]  driver_register+0x58/0x100
 [  347.623998]  __auxiliary_driver_register+0x6a/0xc0
 [  347.624499]  ? driver_register+0xae/0x100
 [  347.624940]  ? 0xffffffffa0893000
 [  347.625329]  mlx5_ib_init+0x16a/0x1e0 [mlx5_ib]
 [  347.625845]  do_one_initcall+0x4a/0x2a0
 [  347.626273]  ? gcov_event+0x2e2/0x3a0
 [  347.626706]  do_init_module+0x8a/0x260
 [  347.627126]  init_module_from_file+0x8b/0xd0
 [  347.627596]  __x64_sys_finit_module+0x1ca/0x2f0
 [  347.628089]  do_syscall_64+0x4c/0x100

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-47694?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-47694?

Apply the vendor's patch.

## Is CVE-2024-47694 being exploited?

There is no known exploitation of CVE-2024-47694 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-47694 and fix it if it is affected.

What it is: CVE-2024-47694 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. 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-2024-47694 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-47694/ (Markdown: https://insights.sbomify.com/CVE-2024-47694/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-47694
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-47694
- OSV: https://osv.dev/vulnerability/CVE-2024-47694

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-47694/
Summaries are generated and may contain mistakes; the official description above is the record.
