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GHSA-Q3VH-MMHJ-MXHR

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-23 15:31

Details

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//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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98923"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:12Z",
    "severity": null
  },
  "details": "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.",
  "id": "GHSA-q3vh-mmhj-mxhr",
  "modified": "2026-10-23T15:31:31Z",
  "published": "2026-10-23T15:31:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98923"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0b04af3d88bb7fc69b2d92457890608860e42365"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9b583795feb51f8d50203228d001760d1344ef01"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b17aa4955e3a694c663ebe99626e4c76ca4f7cfb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bb756b11ad63832ebee58caf9e8f9381eaecff9f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fddc90d4af4550af410f52d11bbf6b5f36443838"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98923 (GCVE-0-2026-98923)

Vulnerability from cvelistv5 – Published: 2026-10-23 12:03 – Updated: 2026-10-23 12:05

Title

arm64: io: Reject non-user protection in ioremap_prot()

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.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7061 records in the last 180 days details

References

5 references

URL	Tags
https://git.kernel.org/stable/c/fddc90d4af4550af4…
https://git.kernel.org/stable/c/0b04af3d88bb7fc69…
https://git.kernel.org/stable/c/b17aa4955e3a694c6…
https://git.kernel.org/stable/c/9b583795feb51f8d5…
https://git.kernel.org/stable/c/bb756b11ad63832eb…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 64858b76ec67c5fc40fef8ec1841fecb78c1ebde , < fddc90d4af4550af410f52d11bbf6b5f36443838 (git) Affected: eeecafce5afffb4da703666ebefbd4d6e2a5abf6 , < 0b04af3d88bb7fc69b2d92457890608860e42365 (git) Affected: 3d64dcc0799c2d6921ba027716b7be721eb19fa8 , < b17aa4955e3a694c663ebe99626e4c76ca4f7cfb (git) Affected: 8f098037139b294050053123ab2bc0f819d08932 , < 9b583795feb51f8d50203228d001760d1344ef01 (git) Affected: 8f098037139b294050053123ab2bc0f819d08932 , < bb756b11ad63832ebee58caf9e8f9381eaecff9f (git) Affected: d1ad8fe7f72d73e1617bac79f2ec7a3bedf47e2a (git) Affected: 6.6.143 , < 6.6.158 (semver) Affected: 6.12.93 , < 6.12.112 (semver) Affected: 6.18.17 , < 6.18.55 (semver) Affected: 6.19.7 , < 6.20 (semver)
Linux	Linux	Affected: 7.0 Unaffected: 0 , < 7.0 (semver) Unaffected: 6.6.158 , ≤ 6.6.* (semver) Unaffected: 6.12.112 , ≤ 6.12.* (semver) Unaffected: 6.18.55 , ≤ 6.18.* (semver) Unaffected: 7.2.9 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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JSON

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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.

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