CVE-2026-98923 (GCVE-0-2026-98923)
Vulnerability from cvelistv5
Published
2026-10-23 12:03
Modified
2026-10-23 12:05
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: arm64: io: Reject non-user protection in ioremap_prot() Mapping a stack-top page via /dev/mem with PROT_NONE and then reading that process's /proc/<pid>/cmdline triggers a spurious WARN in ioremap_prot() through generic_access_phys(): WARNING: ./arch/arm64/include/asm/io.h:275 at generic_access_phys Call trace: generic_access_phys+0x1c8/0x228 (P) __access_remote_vm+0x2b4/0x398 access_remote_vm+0x14/0x30 get_mm_cmdline+0xf8/0x2a0 proc_pid_cmdline_read+0x68/0x120 generic_access_phys() passes the protection derived from the user PTE to ioremap_prot(). On arm64, a PROT_NONE mapping is represented by a present-invalid PTE, so pte_present() still returns true and the protection reaches ioremap_prot(). A PROT_NONE mapping does not have PTE_USER, causing the existing WARN_ON_ONCE() in ioremap_prot() to fire even though this is a valid user mapping. Execute-only mappings have the same issue and must not be readable through this path either. ioremap_prot() should therefore reject protection values without PTE_USER without warning. This makes the access fail cleanly for PROT_NONE and execute-only mappings while retaining the existing user-protection contract.
References
Impacted products
Vendor Product Version
Linux Linux Version: 64858b76ec67c5fc40fef8ec1841fecb78c1ebde
Version: eeecafce5afffb4da703666ebefbd4d6e2a5abf6
Version: 3d64dcc0799c2d6921ba027716b7be721eb19fa8
Version: 8f098037139b294050053123ab2bc0f819d08932
Version: 8f098037139b294050053123ab2bc0f819d08932
Version: d1ad8fe7f72d73e1617bac79f2ec7a3bedf47e2a
Version: 6.6.143   ≤
Version: 6.12.93   ≤
Version: 6.18.17   ≤
Version: 6.19.7   ≤
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: io: Reject non-user protection in ioremap_prot()\n\nMapping a stack-top page via /dev/mem with PROT_NONE and then\nreading that process\u0027s /proc/\u003cpid\u003e/cmdline triggers a spurious WARN\nin ioremap_prot() through generic_access_phys():\n\n  WARNING: ./arch/arm64/include/asm/io.h:275 at generic_access_phys\n  Call trace:\n    generic_access_phys+0x1c8/0x228 (P)\n    __access_remote_vm+0x2b4/0x398\n    access_remote_vm+0x14/0x30\n    get_mm_cmdline+0xf8/0x2a0\n    proc_pid_cmdline_read+0x68/0x120\n\ngeneric_access_phys() passes the protection derived from the user PTE\nto ioremap_prot(). On arm64, a PROT_NONE mapping is represented by a\npresent-invalid PTE, so pte_present() still returns true and the\nprotection reaches ioremap_prot().\n\nA PROT_NONE mapping does not have PTE_USER, causing the existing\nWARN_ON_ONCE() in ioremap_prot() to fire even though this is a valid\nuser mapping. Execute-only mappings have the same issue and must not\nbe readable through this path either.\n\nioremap_prot() should therefore reject protection values without\nPTE_USER without warning. This makes the access fail cleanly for\nPROT_NONE and execute-only mappings while retaining the existing\nuser-protection contract."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T12:05:45.179Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838"
        },
        {
          "url": "https://git.kernel.org/stable/c/0b04af3d88bb7fc69b2d92457890608860e42365"
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        {
          "url": "https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01"
        },
        {
          "url": "https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f"
        }
      ],
      "title": "arm64: io: Reject non-user protection in ioremap_prot()",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98923",
    "datePublished": "2026-10-23T12:03:28.027Z",
    "dateReserved": "2026-09-25T10:25:14.380Z",
    "dateUpdated": "2026-10-23T12:05:45.179Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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