alpha: fix user-space corruption during memory compaction_CVE-2026-43258

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nalpha: fix user-space corruption during memory compaction\n\nAlpha systems can suffer sporadic user-space crashes and heap\ncorruption when memory compaction is enabled.\n\nSymptoms include SIGSEGV, glibc allocator failures (e.g. \"unaligned\ntcache chunk\"), and compiler internal errors. The failures disappear\nwhen compaction is disabled or when using global TLB invalidation.\n\nThe root cause is insufficient TLB shootdown during page migration.\nAlpha relies on ASN-based MM context rollover for instruction cache\ncoherency, but this alone is not sufficient to prevent stale data or\ninstruction translations from surviving migration.\n\nFix this by introducing a migration-specific helper that combines:\n  - MM context invalidation (ASN rollover),\n  - immediate per-CPU TLB invalidation (TBI),\n  - synchronous cross-CPU shootdown when required.\n\nThe helper is used only by migration/compaction paths to avoid changing\nglobal TLB semantics.\n\nAdditionally, update flush_tlb_other(), pte_clear(), to use\nREAD_ONCE()/WRITE_ONCE() for correct SMP memory ordering.\n\nThis fixes observed crashes on both UP and SMP Alpha systems.",
    "published": "2026-05-06T11:28:46.536Z",
    "modified": "2026-05-08T12:41:39.777Z",
    "type": "cve",
    "title": "alpha: fix user-space corruption during memory compaction",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6\nhttps://git.kernel.org/stable/c/03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f\nhttps://git.kernel.org/stable/c/bab8d762a8dbb816b10011e13b87d1bca91e5f77\nhttps://git.kernel.org/stable/c/dd5712f3379cfe760267cdd28ff957d9ab4e51c7",
    "id": "CVE-2026-43258",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux a48d07afdf18212de22b959715b16793c5a6e57a\nLinux Linux a48d07afdf18212de22b959715b16793c5a6e57a\nLinux Linux a48d07afdf18212de22b959715b16793c5a6e57a\nLinux Linux a48d07afdf18212de22b959715b16793c5a6e57a\nLinux Linux 2.6.16",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "a48d07afdf18212de22b959715b16793c5a6e57a",
    "vendor": "Linux",
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    "ai_score": 0
}