CVE-2026-90413 Linux kernel CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, system administrators responsible for Linux systems, security teams responsible for monitoring and incident response.

Why it matters

This vulnerability in the Linux kernel's iSCSI implementation can lead to out-of-bounds reads and potentially cause denial of service or other impacts. Linux kernel developers and maintainers, Linux distribution maintainers, system administrators, and security teams should assess exposure and prioritize patching and remediation efforts.

• Denial of service due to out-of-bounds reads
• Potential for data breaches or unauthorized access
• Need for patching and remediation efforts
• Potential for exploitation by malicious initiators

Technical summary

The Linux kernel's iSCSI implementation does not validate the declared length of login PDUs against the actual received data length. This can cause out-of-bounds reads when processing login PDUs. An initiator can exploit this by declaring a longer length than it sends, causing the kernel to read beyond the buffer's end. The vulnerability is due to the isert_rx_login_req function not validating the declared length of the login PDU against the actual received data length. This issue can lead to a denial of service or potentially other impacts. Linux kernel developers and maintainers, Linux distribution maintainers, system administrators, and security teams should assess exposure and prioritize patching and The 7

Defensive priority

High

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel.
• Restrict access to the iSCSI service to trusted initiators.
• Monitor kernel logs for signs of exploitation attempts.
• Perform a thorough review of system logs to identify potential exploitation attempts.
• Update asset inventory to track systems that may be affected by this vulnerability.
• Consider implementing compensating controls for exposed systems while remediation is scheduled and verified.
• Schedule and verify remediation efforts for exposed systems through normal change control processes.

Evidence notes

The vulnerability was introduced in the Linux kernel's iSCSI implementation. The isert_rx_login_req function does not validate the declared length of the login PDU against the actual received data length. This can cause out-of-bounds reads when processing login PDUs.

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.