Summary
In the Linux kernel, the following vulnerability has been resolved: igc: don't fail igc_probe()...
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:
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
Impact
CVE-2025-39956 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-39956? CVE-2025-39956 is a medium-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2025-39956? CVE-2025-39956 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-39956? No fixed version is listed for CVE-2025-39956 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-39956 exploitable, and should I be worried? Whether CVE-2025-39956 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-39956 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.