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GHSA-9RPR-C8J9-PWGC

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32
VLAI
Details

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

openrisc: fix arbitrary kernel memory access via or1k_atomic syscall

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly.

l.lwz   r29,0(r4)
l.lwz   r27,0(r5)
l.sw    0(r4),r27
l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context.

Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT.

[shorne@gmail.com: fix comment style]

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-89489"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:30Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nopenrisc: fix arbitrary kernel memory access via or1k_atomic syscall\n\nsys_or1k_atomic() (syscall 244 in the \"or1k\" ABI) takes two user\npointers, v1 and v2, and swaps the words they point to in hand-written\nassembly.\n\n    l.lwz   r29,0(r4)\n    l.lwz   r27,0(r5)\n    l.sw    0(r4),r27\n    l.sw    0(r5),r29\n\nThe pointers are not checked with access_ok(). The four memory\naccesses also have no exception table entries.\n\nA caller passes a kernel address as either pointer, and the syscall\nreads from and writes to it directly.\n\nThis gives an unprivileged process a kernel read/write primitive. It\noverwrites kernel data such as the sys_call_table, gaining code\nexecution in kernel context.\n\nCheck both pointers before entering the critical section. Add fixups\nfor the four memory accesses so faults on valid but unmapped user\naddresses return -EFAULT.\n\n[shorne@gmail.com: fix comment style]",
  "id": "GHSA-9rpr-c8j9-pwgc",
  "modified": "2026-09-14T15:32:26Z",
  "published": "2026-09-11T21:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89489"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1f2e92e499d863f81df1732af59b4a3559969193"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/497cba0b02e5555d99fe9ee1dc478af743ab7f7a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/574ae2ac2b314aa33498cd2c28add106cbe644f2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78004e9a87f240df03e2f73120d291763c32e0a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a520e8cac54fb403f3800125b606f55fcad42cb9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b53435c079c78f89f70a62dd5a322cca4e292b34"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bf310718c6fa6adeee06d207a55489546d860e2c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d64a75369cd0f2ee79afcc9d9ca34a3890989379"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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