# CVE-2025-68790: net/mlx5: Fix double unregister of HCA_PORTS component

> A use-after-free in the Linux kernel mlx5 driver causes kernel panics during PCI error recovery, leading to denial of service.

- **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:** 13 Jan 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-68790, GHSA-r4v9-6rcf-whc8, UBUNTU-CVE-2025-68790

## What is CVE-2025-68790?

CVE-2025-68790 is an use after free vulnerability in Linux, published on 13 Jan 2026. 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:

net/mlx5: Fix double unregister of HCA_PORTS component

Clear hca_devcom_comp in device's private data after unregistering it in
LAG teardown. Otherwise a slightly lagging second pass through
mlx5_unload_one() might try to unregister it again and trip over
use-after-free.

On s390 almost all PCI level recovery events trigger two passes through
mxl5_unload_one() - one through the poll_health() method and one through
mlx5_pci_err_detected() as callback from generic PCI error recovery.
While testing PCI error recovery paths with more kernel debug features
enabled, this issue reproducibly led to kernel panics with the following
call chain:

 Unable to handle kernel pointer dereference in virtual kernel address space
 Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6803 ESOP-2 FSI
 Fault in home space mode while using kernel ASCE.
 AS:00000000705c4007 R3:0000000000000024
 Oops: 0038 ilc:3 [#1]SMP

 CPU: 14 UID: 0 PID: 156 Comm: kmcheck Kdump: loaded Not tainted
      6.18.0-20251130.rc7.git0.16131a59cab1.300.fc43.s390x+debug #1 PREEMPT

 Krnl PSW : 0404e00180000000 0000020fc86aa1dc (__lock_acquire+0x5c/0x15f0)
            R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
 Krnl GPRS: 0000000000000000 0000020f00000001 6b6b6b6b6b6b6c33 0000000000000000
            0000000000000000 0000000000000000 0000000000000001 0000000000000000
            0000000000000000 0000020fca28b820 0000000000000000 0000010a1ced8100
            0000010a1ced8100 0000020fc9775068 0000018fce14f8b8 0000018fce14f7f8
 Krnl Code: 0000020fc86aa1cc: e3b003400004        lg      %r11,832
            0000020fc86aa1d2: a7840211           brc     8,0000020fc86aa5f4
           *0000020fc86aa1d6: c09000df0b25       larl    %r9,0000020fca28b820
           >0000020fc86aa1dc: d50790002000       clc     0(8,%r9),0(%r2)
            0000020fc86aa1e2: a7840209           brc     8,0000020fc86aa5f4
            0000020fc86aa1e6: c0e001100401       larl    %r14,0000020fca8aa9e8
            0000020fc86aa1ec: c01000e25a00       larl    %r1,0000020fca2f55ec
            0000020fc86aa1f2: a7eb00e8           aghi    %r14,232

 Call Trace:
  __lock_acquire+0x5c/0x15f0
  lock_acquire.part.0+0xf8/0x270
  lock_acquire+0xb0/0x1b0
  down_write+0x5a/0x250
  mlx5_detach_device+0x42/0x110 [mlx5_core]
  mlx5_unload_one_devl_locked+0x50/0xc0 [mlx5_core]
  mlx5_unload_one+0x42/0x60 [mlx5_core]
  mlx5_pci_err_detected+0x94/0x150 [mlx5_core]
  zpci_event_attempt_error_recovery+0xcc/0x388

## Which versions are affected by CVE-2025-68790?


## How do I fix CVE-2025-68790?

Apply the vendor's patch.

## Is CVE-2025-68790 being exploited?

There is no known exploitation of CVE-2025-68790 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68790 and fix it if it is affected.

What it is: CVE-2025-68790 is an use after free vulnerability in Linux, published on 13 Jan 2026. 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-2025-68790 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-2025-68790/ (Markdown: https://insights.sbomify.com/CVE-2025-68790/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68790
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68790
- OSV: https://osv.dev/vulnerability/CVE-2025-68790

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68790/
Summaries are generated and may contain mistakes; the official description above is the record.