mei: vsc: Fix fortify-panic caused by invalid counted_by() use

{
  "id": "654f89e3ec16bcf2498538f5c6cc54ea39307f0fa8819a5c5c4fc2a9dee40745",
  "url": "https://osv.dev/vulnerability/CVE-2025-37816",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mei: vsc: Fix fortify-panic caused by invalid counted_by() use",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mei: vsc: Fix fortify-panic caused by invalid counted_by() use gcc 15 honors the __counted_by(len) attribute on vsc_tp_packet.buf[] and the vsc-tp.c code is using this in a wrong way. len does not contain the available size in the buffer, it contains the actual packet length *without* the crc. So as soon as vsc_tp_xfer() tries to add the crc to buf[] the fortify-panic handler gets triggered: [ 80.842193] memcpy: detected buffer overflow: 4 byte write of buffer size 0 [ 80.842243] WARNING: CPU: 4 PID: 272 at lib/string_helpers.c:1032 __fortify_report+0x45/0x50 ... [ 80.843175] __fortify_panic+0x9/0xb [ 80.843186] vsc_tp_xfer.cold+0x67/0x67 [mei_vsc_hw] [ 80.843210] ? seqcount_lockdep_reader_access.constprop.0+0x82/0x90 [ 80.843229] ? lockdep_hardirqs_on+0x7c/0x110 [ 80.843250] mei_vsc_hw_start+0x98/0x120 [mei_vsc] [ 80.843270] mei_reset+0x11d/0x420 [mei] The easiest fix would be to just drop the counted-by but with the exception of the ack buffer in vsc_tp_xfer_helper() which only contains enough room for the packet-header, all other uses of vsc_tp_packet always use a buffer of VSC_TP_MAX_XFER_SIZE bytes for the packet. Instead of just dropping the counted-by, split the vsc_tp_packet struct definition into a header and a full-packet definition and use a fixed size buf[] in the packet definition, this way fortify-source buffer overrun checking still works when enabled.",
    "evidence": "osv:CVE-2025-37816",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.26",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.14.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-37816",
      "aliases": [
        "CVE-2025-37816"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "566f5ca9768075e453b7b51a397733968df4287d"
                },
                {
                  "fixed": "3e243378f27cc7d11682a3ad720228b0723affa5"
                },
                {
                  "fixed": "ac04663c67f244810b3492e9ecd9f7cdbefeca2d"
                },
                {
                  "fixed": "00f1cc14da0f06d2897b8c528df7c7dcf1b8da50"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-37816.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.8.0"
                },
                {
                  "fixed": "6.12.26"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.14.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-37816.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.052088384Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/00f1cc14da0f06d2897b8c528df7c7dcf1b8da50",
        "https://git.kernel.org/stable/c/3e243378f27cc7d11682a3ad720228b0723affa5",
        "https://git.kernel.org/stable/c/ac04663c67f244810b3492e9ecd9f7cdbefeca2d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37816.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-37816",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37816.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-37816",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 489401,
  "published_at": "2025-05-08T06:26:12.063+00:00"
}