Vulnerability in Linux kernel (CVE-2025-39956)
Summary
Vulnerability in Linux kernel (CVE-2025-39956). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
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
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2025-39956 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-39956" on the vendor's site.
CVE-2025-39956 (Linux kernel) — CVSS v3 7.8
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2025-39956 linux-lts Fixed in: 6.12.51-r0
- Debian DEBIAN-CVE-2025-39956 linux Fixed in: 6.12.57-1
- Ubuntu UBUNTU-CVE-2025-39956 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org