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CVE-2022-50675

Estado: AplazadaSin puntuar—

In the Linux kernel, the following vulnerability has been resolved:

arm64: mte: Avoid setting PG_mte_tagged if no tags cleared or restored

Prior to commit 69e3b846d8a7 ("arm64: mte: Sync tags for pages where PTE is untagged"), mte_sync_tags() was only called for pte_tagged() entries (those mapped with PROT_MTE). Therefore mte_sync_tags() could safely use test_and_set_bit(PG_mte_tagged, &page->flags) without inadvertently setting PG_mte_tagged on an untagged page.

The above commit was required as guests may enable MTE without any control at the stage 2 mapping, nor a PROT_MTE mapping in the VMM.

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However, the side-effect was that any page with a PTE that looked like swap (or migration) was getting PG_mte_tagged set automatically. A subsequent page copy (e.g. migration) copied the tags to the destination page even if the tags were owned by KASAN.

This issue was masked by the page_kasan_tag_reset() call introduced in commit e5b8d9218951 ("arm64: mte: reset the page tag in page->flags"). When this commit was reverted (20794545c146), KASAN started reporting access faults because the overriding tags in a page did not match the original page->flags (with CONFIG_KASAN_HW_TAGS=y):

Move the PG_mte_tagged bit setting from mte_sync_tags() to the actual place where tags are cleared (mte_sync_page_tags()) or restored (mte_restore_tags()).

Detalles técnicos trazas, registros y código del informe original
  BUG: KASAN: invalid-access in copy_page+0x10/0xd0 arch/arm64/lib/copy_page.S:26
  Read at addr f5ff000017f2e000 by task syz-executor.1/2218
  Pointer tag: [f5], memory tag: [f2]

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2022-50675",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "69e3b846d8a753f9f279f29531ca56b0f7563ad0",
              "lessThan": "918002bdbe4328c8c0164a22e8ebf2384b80dc23",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "69e3b846d8a753f9f279f29531ca56b0f7563ad0",
              "lessThan": "749e9fc18b1e1a3f93a9512e91bd7f93002d2821",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "69e3b846d8a753f9f279f29531ca56b0f7563ad0",
              "lessThan": "a8e5e5146ad08d794c58252bab00b261045ef16d",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/arm64/kernel/mte.c",
            "arch/arm64/mm/mteswap.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.14",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.82",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.0.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.0.*"
            },
            {
              "status": "unaffected",
              "version": "6.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/arm64/kernel/mte.c",
            "arch/arm64/mm/mteswap.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-12-09T16:17:19.730",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/749e9fc18b1e1a3f93a9512e91bd7f93002d2821",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/918002bdbe4328c8c0164a22e8ebf2384b80dc23",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a8e5e5146ad08d794c58252bab00b261045ef16d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: mte: Avoid setting PG_mte_tagged if no tags cleared or restored\n\nPrior to commit 69e3b846d8a7 (\"arm64: mte: Sync tags for pages where PTE\nis untagged\"), mte_sync_tags() was only called for pte_tagged() entries\n(those mapped with PROT_MTE). Therefore mte_sync_tags() could safely use\ntest_and_set_bit(PG_mte_tagged, &page->flags) without inadvertently\nsetting PG_mte_tagged on an untagged page.\n\nThe above commit was required as guests may enable MTE without any\ncontrol at the stage 2 mapping, nor a PROT_MTE mapping in the VMM.\nHowever, the side-effect was that any page with a PTE that looked like\nswap (or migration) was getting PG_mte_tagged set automatically. A\nsubsequent page copy (e.g. migration) copied the tags to the destination\npage even if the tags were owned by KASAN.\n\nThis issue was masked by the page_kasan_tag_reset() call introduced in\ncommit e5b8d9218951 (\"arm64: mte: reset the page tag in page->flags\").\nWhen this commit was reverted (20794545c146), KASAN started reporting\naccess faults because the overriding tags in a page did not match the\noriginal page->flags (with CONFIG_KASAN_HW_TAGS=y):\n\n  BUG: KASAN: invalid-access in copy_page+0x10/0xd0 arch/arm64/lib/copy_page.S:26\n  Read at addr f5ff000017f2e000 by task syz-executor.1/2218\n  Pointer tag: [f5], memory tag: [f2]\n\nMove the PG_mte_tagged bit setting from mte_sync_tags() to the actual\nplace where tags are cleared (mte_sync_page_tags()) or restored\n(mte_restore_tags())."
    }
  ],
  "lastModified": "2026-06-17T05:23:58.663",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}