GHSA-RCQ2-MGHH-WCF4

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-05-27 15:33
VLAI
Details

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

ibmasm: fix OOB reads in command_file_write due to missing size checks

The command_file_write() handler allocates a kernel buffer of exactly count bytes and copies user data into it, but does not validate the buffer against the dot command protocol before passing it to get_dot_command_size() and get_dot_command_timeout().

Since both the allocation size (count) and the header fields (command_size, data_size) are independently user-controlled, an attacker can cause get_dot_command_size() to return a value exceeding the allocation, triggering OOB reads in get_dot_command_timeout() and an out-of-bounds memcpy_toio() that leaks kernel heap memory to the service processor.

Fix with two guards: reject writes smaller than sizeof(struct dot_command_header) before allocation, then after copying user data reject commands where the buffer is smaller than the total size declared by the header (sizeof(header) + command_size + data_size). This ensures all subsequent header and payload field accesses stay within the buffer.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-45994"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:16Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nibmasm: fix OOB reads in command_file_write due to missing size checks\n\nThe command_file_write() handler allocates a kernel buffer of exactly\ncount bytes and copies user data into it, but does not validate the\nbuffer against the dot command protocol before passing it to\nget_dot_command_size() and get_dot_command_timeout().\n\nSince both the allocation size (count) and the header fields (command_size,\ndata_size) are independently user-controlled, an attacker can cause\nget_dot_command_size() to return a value exceeding the allocation,\ntriggering OOB reads in get_dot_command_timeout() and an out-of-bounds\nmemcpy_toio() that leaks kernel heap memory to the service processor.\n\nFix with two guards: reject writes smaller than sizeof(struct\ndot_command_header) before allocation, then after copying user data\nreject commands where the buffer is smaller than the total size declared\nby the header (sizeof(header) + command_size + data_size). This ensures\nall subsequent header and payload field accesses stay within the buffer.",
  "id": "GHSA-rcq2-mghh-wcf4",
  "modified": "2026-05-27T15:33:20Z",
  "published": "2026-05-27T15:33:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45994"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0eb09f737428e482a32a2e31e5e223f2b35a71d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a672682d39dd34e2b5ba4feb436723bed65125ff"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aefc1a97da17d8309974690c8a03e439a91ebb1c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d0fb4d1dc43f8d5179917a2daaa82680993d4cdf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee5737891464030a189837467df3b81a273718ad"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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