# CVE-2025-39956: igc: don't fail igc_probe() on LED setup error

> A kernel panic occurs in the igc driver if LED setup fails during probe, causing a denial of service.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 9 Oct 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-39956, DEBIAN-CVE-2025-39956, GHSA-486r-g5rc-cq67, ROOT-OS-DEBIAN-13-CVE-2025-39956, UBUNTU-CVE-2025-39956

## What is CVE-2025-39956?

CVE-2025-39956 is a high-severity vulnerability in Linux kernel, published on 9 Oct 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:

igc: don't fail igc_probe() on LED setup error

When igc_led_setup() fails, igc_probe() fails and triggers kernel panic
in free_netdev() since unregister_netdev() is not called. [1]
This behavior can be tested using fault-injection framework, especially
the failslab feature. [2]

Since LED support is not mandatory, treat LED setup failures as
non-fatal and continue probe with a warning message, consequently
avoiding the kernel panic.

[1]
 kernel BUG at net/core/dev.c:12047!
 Oops: invalid opcode: 0000 [#1] SMP NOPTI
 CPU: 0 UID: 0 PID: 937 Comm: repro-igc-led-e Not tainted 6.17.0-rc4-enjuk-tnguy-00865-gc4940196ab02 #64 PREEMPT(voluntary)
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
 RIP: 0010:free_netdev+0x278/0x2b0
 [...]
 Call Trace:
  <TASK>
  igc_probe+0x370/0x910
  local_pci_probe+0x3a/0x80
  pci_device_probe+0xd1/0x200
 [...]

[2]
 #!/bin/bash -ex

 FAILSLAB_PATH=/sys/kernel/debug/failslab/
 DEVICE=0000:00:05.0
 START_ADDR=$(grep " igc_led_setup" /proc/kallsyms \
         | awk '{printf("0x%s", $1)}')
 END_ADDR=$(printf "0x%x" $((START_ADDR + 0x100)))

 echo $START_ADDR > $FAILSLAB_PATH/require-start
 echo $END_ADDR > $FAILSLAB_PATH/require-end
 echo 1 > $FAILSLAB_PATH/times
 echo 100 > $FAILSLAB_PATH/probability
 echo N > $FAILSLAB_PATH/ignore-gfp-wait

 echo $DEVICE > /sys/bus/pci/drivers/igc/bind

## Which versions are affected by CVE-2025-39956?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-39956?

Apply the vendor's patch.

## Is CVE-2025-39956 being exploited?

There is no known exploitation of CVE-2025-39956 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-2025-39956 and fix it if it is affected.

What it is: CVE-2025-39956 is a high-severity vulnerability in Linux kernel, published on 9 Oct 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-2025-39956 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-2025-39956/ (Markdown: https://insights.sbomify.com/CVE-2025-39956/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39956
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39956
- OSV: https://osv.dev/vulnerability/CVE-2025-39956

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39956/
Summaries are generated and may contain mistakes; the official description above is the record.