CVE-2026-43258: In the Linux kernel, the following vulnerability has been resolved: alpha: fix user-space corruption during memory compaction Alpha systems can suff...

Description

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.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.14%

3.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 2.6.16.1, < 6.12.75
Linux	Linux Kernel	>= 6.13, < 6.18.16
Linux	Linux Kernel	>= 6.19, < 6.19.6
Linux	Linux Kernel	2.6.16

References

Timeline

Published: May 6, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-43258?

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.

How severe is CVE-2026-43258?

CVE-2026-43258 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.

How do I fix CVE-2026-43258?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.