PatchSiren cyber security CVE debrief
CVE-2025-38735 Cert Portal CVE debrief
CVE-2025-38735 describes an availability issue in the Linux kernel gve driver. According to the advisory text, a shutdown path tears down internal driver data structures, but the device can still remain visible long enough for an ethtool operation to be dispatched. If that happens after shutdown(), the driver may dereference freed or NULL pointers and crash the kernel. The advisory says the fix is to call netif_device_detach() during shutdown() so the ethtool ioctl path will not dispatch operations to the driver. The issue is rated CVSS 5.5/Medium and is most relevant where shutdowns can be forced or otherwise do not fully quiesce userspace before device access stops.
- Vendor
- Cert Portal
- Product
- Siemens SIMATIC CN 4100 vers:intdot/<5.0
- CVSS
- MEDIUM 5.5
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-12
- Original CVE updated
- 2026-05-14
- Advisory published
- 2026-05-12
- Advisory updated
- 2026-05-14
Who should care
Linux and OT/edge operators who rely on systems covered by the advisory, especially environments that can experience forced shutdowns or post-shutdown management activity. It also matters for administrators of systems using the affected gve network driver path described in the source advisory.
Technical summary
The vulnerability is a race/teardown flaw in the gve shutdown path. shutdown() stops DMA and dismantles most internal state, but the netdev can still be visible. If an ethtool operation is invoked afterward, the driver can touch freed or NULL data and panic the kernel. The fix prevents driver dispatch after shutdown by detaching the device with netif_device_detach().
Defensive priority
Medium
Recommended defensive actions
- Apply the vendor-provided update to version 5.0 or later where applicable.
- Verify whether any deployed systems actually match the advisory's affected product mapping before scheduling remediation.
- Review shutdown and maintenance procedures for systems that may still accept management operations during forced power-off or reboot events.
- Prioritize patching or maintenance on systems where kernel panics during shutdown would cause service interruption or recovery risk.
- Monitor for unexpected crashes or failed shutdowns on affected hosts until remediation is complete.
Evidence notes
The supplied CISA CSAF source states that an ethtool operation after shutdown() can dereference freed or NULL pointers and cause a kernel panic, and that the fix is to call netif_device_detach() in shutdown(). The same source also includes a Siemens ProductCERT remediation reference to update to V5.0 or later. However, the advisory metadata maps the CVE to Siemens SIMATIC CN 4100 vers:intdot/<5.0 while the vulnerability description itself refers to the Linux kernel gve driver, so the product mapping should be treated as low-confidence and verified before actioning.
Official resources
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CVE-2025-38735 CVE record
CVE.org
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CVE-2025-38735 NVD detail
NVD
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Source item URL
cisa_csaf
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Source reference
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Reference
CISA published the advisory on 2026-05-12 and republished it on 2026-05-14. Timing in this debrief follows the CVE/source dates provided, not the report generation date. The source does not list the issue as a CISA KEV entry.