CVE-2026-43258 Linux CVE debrief

Who should care

Linux system administrators, security teams, and developers using Alpha systems with Linux kernel versions 2.6.16.1 to 6.19.6, 6.13 to 6.18.16 should assess exposure, apply patches, and monitor systems for anomalies. They should also consider compensating controls if patches cannot be applied.

Why it matters

Linux kernel vulnerability allows user-space corruption during memory compaction on Alpha systems, leading to sporadic crashes and heap corruption. Assess exposure, apply patches, and monitor systems.

• Verify and apply patches to prevent user-space corruption
• Assess exposure for Alpha systems running affected Linux kernel versions
• Monitor for anomalies and system crashes
• Consider compensating controls if patches cannot be applied

Technical summary

The Linux kernel vulnerability causes user-space corruption during memory compaction on Alpha systems, resulting in sporadic crashes and heap corruption. The root cause is insufficient TLB shootdown during page migration. A migration-specific helper has been introduced to combine MM context invalidation, immediate per-CPU TLB invalidation, and synchronous cross-CPU shootdown. This helper is used only by migration/compaction paths to avoid changing global TLB semantics. Additionally, update flush_tlb_other(), pte_clear(), to use READ_ONCE()/WRITE_ONCE() for correct SMP memory ordering.

Defensive priority

Assess exposure and apply patches for Linux kernel versions 2.6.16.1 to 6.19.6, 6.13 to 6.18.16.

Recommended defensive actions

• Assess exposure for Linux kernel versions 2.6.16.1 to 6.19.6, 6.13 to 6.18.16
• Apply patches from kernel.org for affected versions
• Verify system integrity and monitor for anomalies
• Consider disabling memory compaction if patches cannot be applied
• 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

Official CVE Program record and NIST NVD detail page provide information on the vulnerability. Patches are available for affected Linux kernel versions. The issue is caused by insufficient TLB shootdown during page migration, which can result in stale data or instruction translations surviving migration. The migration-specific helper combines MM context invalidation, immediate per-CPU TLB invalidation, and synchronous cross-CPU shootdown to address this issue.

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.