CVE-2026-98754 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, system administrators responsible for Linux kernel updates and security patches, and operators of systems using the affected Linux kernel versions should assess exposure and prioritize remediation. They should verify Linux kernel versions, review system configurations, and monitor system logs for potential exploitation attempts.

Why it matters

A use-after-free vulnerability exists in the Linux kernel's tty: vcc component, allowing a race condition between vcc_cleanup and vcc_event LDC callbacks. This can cause a use-after-free when the callback dereferences tty->port after cleanup has already destroyed and freed it. Linux kernel developers and maintainers, as well as system administrators responsible for Linux kernel updates and security patches, should assess exposure and prioritize remediation.

• Verify Linux kernel versions and apply patches to mitigate the vulnerability
• Review system configurations and ensure proper locking mechanisms are in place
• Monitor system logs for potential exploitation attempts

Technical summary

The vcc_cleanup function in the Linux kernel's tty: vcc component sets port->tty to NULL without holding port->lock, allowing a race condition with vcc_event LDC callbacks that read port->tty under port->lock and then use tty->port. This can cause a use-after-free when the callback dereferences tty->port after cleanup has already destroyed and freed it. The vulnerability affects Linux kernel developers and maintainers, system administrators responsible for Linux kernel updates and security patches, and operators of systems using the affected Linux kernel versions.

Defensive priority

Verify Linux kernel versions and apply patches to mitigate the vulnerability.

Recommended defensive actions

• Verify Linux kernel versions and apply patches to mitigate the vulnerability.
• Review system configurations and ensure proper locking mechanisms are in place.
• Monitor system logs for potential exploitation attempts.
• Perform a thorough review of the Linux kernel codebase to identify potential similar vulnerabilities.
• Implement compensating controls for exposed systems while remediation is scheduled and verified.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• 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 information on the vulnerability, but details on affected versions, exploitation, and remediation are limited. Linux kernel developers and maintainers, as well as system administrators responsible for Linux kernel updates and security patches, should verify Linux kernel versions, review system configurations, and monitor system logs for potential exploitation attempts.

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.