CVE-2026-90170 Linux CVE debrief

Who should care

Linux kernel administrators and developers, particularly those using ksmbd, should verify and apply patches to prevent potential slab-out-of-bounds reads. They should review the CVE record and NVD entry for more information and monitor system logs for signs of slab-out-of-bounds reads.

Why it matters

CVE-2026-90170 is a Linux kernel vulnerability in ksmbd that requires patching to prevent slab-out-of-bounds reads. Linux kernel administrators and developers, particularly those using ksmbd, should verify and apply patches.

• Verify Linux kernel versions and apply patches for ksmbd vulnerabilities to prevent potential slab-out-of-bounds reads
• Review system configurations for ksmbd usage and potential exposure
• Monitor system logs for signs of slab-out-of-bounds reads

Technical summary

The Linux kernel vulnerability involves ksmbd's validation of IPC response lengths before dereferencing its fields, potentially leading to a slab-out-of-bounds read. The vulnerability was reported and patched, and Linux kernel administrators and developers, particularly those using ksmbd, should verify and apply patches to prevent potential slab-out-of-bounds reads. The patch addresses the issue by validating the IPC response length before accessing its fields, preventing the slab-out-of-bounds read. The vulnerability was introduced in the Linux kernel's ksmbd module, which did not properly validate IPC response lengths.

Defensive priority

Verify and apply patches for Linux kernel vulnerabilities, particularly those affecting ksmbd, to prevent potential slab-out-of-bounds reads.

Recommended defensive actions

• Verify Linux kernel versions and apply patches for ksmbd vulnerabilities
• Review system configurations for ksmbd usage and potential exposure
• Monitor system logs for signs of slab-out-of-bounds reads
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including a KASAN report indicating a slab-out-of-bounds read in ipc_msg_send_request. The vulnerability was introduced in the Linux kernel's ksmbd module, which did not properly validate IPC response lengths. The issue was reported and patched, and the patch has been applied to prevent potential slab-out-of-bounds reads. Linux kernel administrators and developers should review the CVE record and NVD entry for more information.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.