GHSA-XQP7-9GQV-6978

Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-06-19 15:33
VLAI
Details

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

arm64: io: Extract user memory type in ioremap_prot()

The only caller of ioremap_prot() outside of the generic ioremap() implementation is generic_access_phys(), which passes a 'pgprot_t' value determined from the user mapping of the target 'pfn' being accessed by the kernel. On arm64, the 'pgprot_t' contains all of the non-address bits from the pte, including the permission controls, and so we end up returning a new user mapping from ioremap_prot() which faults when accessed from the kernel on systems with PAN:

| Unable to handle kernel read from unreadable memory at virtual address ffff80008ea89000 | ... | Call trace: | __memcpy_fromio+0x80/0xf8 | generic_access_phys+0x20c/0x2b8 | __access_remote_vm+0x46c/0x5b8 | access_remote_vm+0x18/0x30 | environ_read+0x238/0x3e8 | vfs_read+0xe4/0x2b0 | ksys_read+0xcc/0x178 | __arm64_sys_read+0x4c/0x68

Extract only the memory type from the user 'pgprot_t' in ioremap_prot() and assert that we're being passed a user mapping, to protect us against any changes in future that may require additional handling. To avoid falsely flagging users of ioremap(), provide our own ioremap() macro which simply wraps __ioremap_prot().

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-23346"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-25T11:16:32Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: io: Extract user memory type in ioremap_prot()\n\nThe only caller of ioremap_prot() outside of the generic ioremap()\nimplementation is generic_access_phys(), which passes a \u0027pgprot_t\u0027 value\ndetermined from the user mapping of the target \u0027pfn\u0027 being accessed by\nthe kernel. On arm64, the \u0027pgprot_t\u0027 contains all of the non-address\nbits from the pte, including the permission controls, and so we end up\nreturning a new user mapping from ioremap_prot() which faults when\naccessed from the kernel on systems with PAN:\n\n  | Unable to handle kernel read from unreadable memory at virtual address ffff80008ea89000\n  | ...\n  | Call trace:\n  |   __memcpy_fromio+0x80/0xf8\n  |   generic_access_phys+0x20c/0x2b8\n  |   __access_remote_vm+0x46c/0x5b8\n  |   access_remote_vm+0x18/0x30\n  |   environ_read+0x238/0x3e8\n  |   vfs_read+0xe4/0x2b0\n  |   ksys_read+0xcc/0x178\n  |   __arm64_sys_read+0x4c/0x68\n\nExtract only the memory type from the user \u0027pgprot_t\u0027 in ioremap_prot()\nand assert that we\u0027re being passed a user mapping, to protect us against\nany changes in future that may require additional handling. To avoid\nfalsely flagging users of ioremap(), provide our own ioremap() macro\nwhich simply wraps __ioremap_prot().",
  "id": "GHSA-xqp7-9gqv-6978",
  "modified": "2026-06-19T15:33:07Z",
  "published": "2026-03-25T12:30:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23346"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3d64dcc0799c2d6921ba027716b7be721eb19fa8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/64858b76ec67c5fc40fef8ec1841fecb78c1ebde"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8f098037139b294050053123ab2bc0f819d08932"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d1ad8fe7f72d73e1617bac79f2ec7a3bedf47e2a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eeecafce5afffb4da703666ebefbd4d6e2a5abf6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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