CVE-2026-74556 Linux CVE debrief

Who should care

Linux kernel maintainers, users, and administrators, especially those using libiscsi_tcp, should assess exposure and apply patches to prevent potential buffer overflows. This includes reviewing Linux kernel versions and configurations, verifying buffer overflow protections in libiscsi_tcp implementations, and monitoring for suspicious SCSI Response traffic. Security teams and vulnerability management teams should also be aware of this vulnerability and its

Why it matters

A critical vulnerability in the Linux kernel's SCSI libiscsi_tcp module allows for a buffer overflow, potentially leading to security issues. Linux kernel maintainers and users should assess exposure and apply patches.

• Verify Linux kernel versions and configurations to assess exposure
• Apply patches to prevent potential buffer overflows
• Monitor for suspicious SCSI Response traffic
• Review libiscsi_tcp implementations for buffer overflow protections

Technical summary

The Linux kernel's SCSI libiscsi_tcp module does not properly bound the data segment for the SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) opcode. This allows for a potential buffer overflow when handling SCSI Response data segments with a DataSegmentLength between 8193 and the negotiated MaxRecvDataSegmentLength. The vulnerability is addressed in various Linux kernel commits. Affected product deployments should be reviewed for exposure, and patches should be applied to prevent potential buffer overflows. Compensating controls, such as monitoring and detection, should be reviewed for exposed systems.

Defensive priority

High priority for Linux kernel maintainers and users, especially those using libiscsi_tcp, to assess exposure and apply patches.

Recommended defensive actions

• Assess exposure by reviewing Linux kernel versions and configurations
• Apply patches from Linux kernel maintainers
• Monitor for suspicious SCSI Response traffic
• Verify buffer overflow protections in libiscsi_tcp implementations
• Review compensating controls for exposed systems while remediation is scheduled and verified
• 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

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, affected versions, and references to patches. However, there is limited information on exploitation or specific attacks.

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.