EUVD-2026-39858
GHSA-vg65-jq85-8q85
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Local trigger via ethtool (PR:L); deadlock causes availability loss (A:H); no confidentiality or integrity impact confirmed by description.
Primary rating from NVD.
CVSS VectorNVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
5DescriptionNVD
In the Linux kernel, the following vulnerability has been resolved:
net: dsa: remove redundant netdev_lock_ops() from conduit ethtool ops
DSA replaces the conduit (master) device's ethtool_ops with its own wrappers that aggregate stats from both the conduit and DSA switch ports. Taking the lock again inside the DSA wrappers causes a deadlock.
Stumbled upon this when booting qemu with fbnic and CONFIG_NET_DSA_LOOP=y (which looks like some kind of testing device that auto-populates the ports of eth0). ethtool -i is enough to deadlock. This means we have basically zero coverage for DSA stuff with real ops locked devs.
Remove the redundant netdev_lock_ops()/netdev_unlock_ops() calls from the DSA conduit ethtool wrappers.
AnalysisAI
Deadlock in the Linux kernel's DSA (Distributed Switch Architecture) subsystem allows a local low-privileged user to hang the kernel network stack by running ethtool against a DSA-configured conduit interface. The DSA subsystem replaces the conduit device's ethtool_ops with aggregating wrappers, but these wrappers redundantly invoke netdev_lock_ops() on a lock already held by the kernel ethtool infrastructure, creating a classic double-lock deadlock. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires all of the following: (1) the Linux kernel compiled with DSA support (CONFIG_NET_DSA enabled, or the loop testing variant CONFIG_NET_DSA_LOOP), (2) a DSA topology actively attached to a conduit (master) Ethernet interface - either real managed switch hardware or the DSA loop test device, and (3) a local user account with permission to invoke ethtool against the conduit interface. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 3.1 base score of 5.5 (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) accurately characterizes this as a local, low-privilege denial-of-service with no confidentiality or integrity impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A local user on a Linux system running DSA-attached network hardware (or the DSA loop testing module) executes `ethtool -i eth0` against the conduit interface. The kernel's ethtool dispatch acquires the netdev lock and enters the DSA wrapper, which attempts to re-acquire the same lock - producing a kernel deadlock that permanently hangs the calling process and renders the conduit interface's ethtool operations unresponsive until reboot. … |
| Remediation | Upgrade to Linux kernel 7.1, 7.0.10, or 6.18.33, which remove the redundant netdev_lock_ops()/netdev_unlock_ops() calls from the DSA conduit ethtool wrappers. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-667 – Improper Locking
View allSame technique Information Disclosure
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External POC / Exploit Code
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