GHSA-C5FX-2729-67QQ

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31
VLAI
Details

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

coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()

When the SMB sink is used as a perf AUX sink, smb_update_buffer() calls smb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring buffer pages. It derives pg_idx = head >> PAGE_SHIFT from @head, which is handle->head, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages normalization is only applied after the first loop iteration.

This leaves the initial page index underived from the buffer size, which can result in an out-of-bounds write past dst_pages[] when head exceeds the AUX buffer size.

Normalize head modulo the AUX buffer size before deriving the page index and offset, mirroring tmc_etr_sync_perf_buffer().

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64402"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:23Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncoresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()\n\nWhen the SMB sink is used as a perf AUX sink, smb_update_buffer() calls\nsmb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring\nbuffer pages. It derives pg_idx = head \u003e\u003e PAGE_SHIFT from @head, which is\nhandle-\u003ehead, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages\nnormalization is only applied after the first loop iteration.\n\nThis leaves the initial page index underived from the buffer size, which\ncan result in an out-of-bounds write past dst_pages[] when head exceeds\nthe AUX buffer size.\n\nNormalize head modulo the AUX buffer size before deriving the page index\nand offset, mirroring tmc_etr_sync_perf_buffer().",
  "id": "GHSA-c5fx-2729-67qq",
  "modified": "2026-07-25T12:31:34Z",
  "published": "2026-07-25T12:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64402"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/38dbc8db8341ccdf8e1e1a067453d33ad751864b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4c5a0a946373da99a80398289b28845b5ae40cd1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/98495b5a4d77dd22e106f462b76e1093a55b29a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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