CVE-2026-23428 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, system administrators responsible for Linux systems, security teams monitoring Linux infrastructure, operators managing Linux-based platforms, and vulnerability management teams responsible for Linux systems.

Why it matters

This vulnerability in the Linux kernel's ksmbd module requires immediate attention from Linux system administrators and security teams. The use-after-free error can lead to potential remote code execution, denial of service, or elevation of privileges on affected systems. It is crucial to review and apply patches from Linux kernel maintainers, implement additional monitoring, restrict access to affected systems, and verify system configurations and inventory for exposure.

• Potential for remote code execution or denial of service
• Elevation of privileges on affected systems
• Data tampering or unauthorized access

Technical summary

The ksmbd module in the Linux kernel is vulnerable to a use-after-free error when handling compound requests. This occurs because the tcon->t_state is not validated before reusing work->tcon. An attacker could potentially exploit this by crafting a sequence of SMB commands that trigger the free of share_conf and then attempt to access it, leading to a use-after-free error. This vulnerability can lead to potential remote code execution, denial of service, or elevation of privileges on affected systems. Linux kernel developers and maintainers should review and apply patches to update the ksmbd module. System administrators responsible for Linux systems should implement additional monitoring to detect potential

Defensive priority

High

Recommended defensive actions

• Review and apply patches from Linux kernel maintainers to update ksmbd module
• Implement additional monitoring to detect potential exploitation attempts
• Restrict access to affected systems and limit SMBv2 compound request usage
• Verify system configurations and inventory for exposure
• Conduct vulnerability scanning to identify potentially affected systems
• Isolate affected systems from the network until patches are applied
• Review system logs for signs of exploitation

Evidence notes

The vulnerability was reported via a KASAN (Kernel Address Sanitizer) report, which indicated a slab-use-after-free error in smb2_write. The issue was resolved through a series of patches applied to the Linux kernel's ksmbd module.

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.