Incorrect Synchronization Affecting kernel6.18-tools-debuginfo package, versions <1:6.18.16-18.222.amzn2023
Threat Intelligence
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Test your applications- Snyk IDSNYK-AMZN2023-KERNEL618TOOLSDEBUGINFO-16883172
- published27 May 2026
- disclosed6 May 2026
Introduced: 6 May 2026
CVE-2026-43258 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 kernel6.18-tools-debuginfo to version 1:6.18.16-18.222.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1702.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel6.18-tools-debuginfo package and not the kernel6.18-tools-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
alpha: fix user-space corruption during memory compaction
Alpha systems can suffer sporadic user-space crashes and heap corruption when memory compaction is enabled.
Symptoms include SIGSEGV, glibc allocator failures (e.g. "unaligned tcache chunk"), and compiler internal errors. The failures disappear when compaction is disabled or when using global TLB invalidation.
The root cause is insufficient TLB shootdown during page migration. Alpha relies on ASN-based MM context rollover for instruction cache coherency, but this alone is not sufficient to prevent stale data or instruction translations from surviving migration.
Fix this by introducing a migration-specific helper that combines:
- MM context invalidation (ASN rollover),
- immediate per-CPU TLB invalidation (TBI),
- synchronous cross-CPU shootdown when required.
The 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.
This fixes observed crashes on both UP and SMP Alpha systems.
References
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-43258
- https://git.kernel.org/stable/c/03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f
- https://git.kernel.org/stable/c/bab8d762a8dbb816b10011e13b87d1bca91e5f77
- https://git.kernel.org/stable/c/d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6
- https://git.kernel.org/stable/c/dd5712f3379cfe760267cdd28ff957d9ab4e51c7