CVE-2026-98903 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel-based systems, particularly those using versions 5.7 or earlier, should assess exposure and prioritize patching. Operators, platform administrators, vulnerability management teams, and security teams should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Why it matters

A race condition vulnerability in the Linux kernel's mailbox: imx module has been identified, which can lead to problems on shared handlers if the 'removed' channel triggers an interrupt. Defenders should prioritize verifying the Linux kernel version and applying patches to address this vulnerability.

• Verify Linux kernel version and apply patches to prevent potential issues
• Review system configurations and update as necessary to prevent potential issues
• Monitor system logs for potential issues related to the vulnerability

Technical summary

The vulnerability is caused by a race condition in the imx_mu_shutdown() function, which can lead to the RX event remaining enabled even after the channel has been shut down. The vulnerability has been resolved by introducing a shutdown flag to signal that the channel is shutting down. This flag is set with the lock held (by imx_mu_xcr_clr_shut()). The unmask side uses imx_mu_xcr_set_act() which only enables the event if the channel has not been shutdown and serialises on the same lock. Affected Linux kernel-based systems, particularly those using versions 5.7 or earlier, should assess exposure and prioritize patching.

Defensive priority

Defenders should prioritize verifying the Linux kernel version and applying patches to address this vulnerability. Systems using Linux kernel versions 5.7 or earlier are affected. The vulnerability has been resolved in later kernel versions.

Recommended defensive actions

• Verify Linux kernel version and apply patches
• Review system configurations and update as necessary
• Monitor system logs for potential issues
• 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
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by a race condition in the imx_mu_shutdown() function, which can lead to the RX event remaining enabled even after the channel has been shut down. The vulnerability has been resolved by introducing a shutdown flag to signal that the channel is shutting down.

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.