CVE-2026-43258 (GCVE-0-2026-43258)

Vulnerability from cvelistv5 – Published: 2026-05-06 11:28 – Updated: 2026-05-06 11:28
VLAI?
Title
alpha: fix user-space corruption during memory compaction
Summary
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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < bab8d762a8dbb816b10011e13b87d1bca91e5f77 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < dd5712f3379cfe760267cdd28ff957d9ab4e51c7 (git)
Create a notification for this product.
    Linux Linux Unaffected: 6.12.75 , ≤ 6.12.* (semver)
Unaffected: 6.18.16 , ≤ 6.18.* (semver)
Unaffected: 6.19.6 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/alpha/include/asm/pgtable.h",
            "arch/alpha/include/asm/tlbflush.h",
            "arch/alpha/mm/Makefile",
            "arch/alpha/mm/tlbflush.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "bab8d762a8dbb816b10011e13b87d1bca91e5f77",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "dd5712f3379cfe760267cdd28ff957d9ab4e51c7",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/alpha/include/asm/pgtable.h",
            "arch/alpha/include/asm/tlbflush.h",
            "arch/alpha/mm/Makefile",
            "arch/alpha/mm/tlbflush.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.75",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-06T11:28:46.536Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6"
        },
        {
          "url": "https://git.kernel.org/stable/c/03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f"
        },
        {
          "url": "https://git.kernel.org/stable/c/bab8d762a8dbb816b10011e13b87d1bca91e5f77"
        },
        {
          "url": "https://git.kernel.org/stable/c/dd5712f3379cfe760267cdd28ff957d9ab4e51c7"
        }
      ],
      "title": "alpha: fix user-space corruption during memory compaction",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43258",
    "datePublished": "2026-05-06T11:28:46.536Z",
    "dateReserved": "2026-05-01T14:12:55.997Z",
    "dateUpdated": "2026-05-06T11:28:46.536Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43258\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-06T12:16:46.650\",\"lastModified\":\"2026-05-06T13:07:51.607\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/bab8d762a8dbb816b10011e13b87d1bca91e5f77\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/dd5712f3379cfe760267cdd28ff957d9ab4e51c7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.