drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup

{
  "id": "9703a2a92bcc0e28f0b18eedc18cbe9ead48e6dbe6958e50f41b0df658a6ac01",
  "url": "https://osv.dev/vulnerability/CVE-2025-68296",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup Protect vga_switcheroo_client_fb_set() with console lock. Avoids OOB access in fbcon_remap_all(). Without holding the console lock the call races with switching outputs. VGA switcheroo calls fbcon_remap_all() when switching clients. The fbcon function uses struct fb_info.node, which is set by register_framebuffer(). As the fb-helper code currently sets up VGA switcheroo before registering the framebuffer, the value of node is -1 and therefore not a legal value. For example, fbcon uses the value within set_con2fb_map() [1] as an index into an array. Moving vga_switcheroo_client_fb_set() after register_framebuffer() can result in VGA switching that does not switch fbcon correctly. Therefore move vga_switcheroo_client_fb_set() under fbcon_fb_registered(), which already holds the console lock. Fbdev calls fbcon_fb_registered() from within register_framebuffer(). Serializes the helper with VGA switcheroo's call to fbcon_remap_all(). Although vga_switcheroo_client_fb_set() takes an instance of struct fb_info as parameter, it really only needs the contained fbcon state. Moving the call to fbcon initialization is therefore cleaner than before. Only amdgpu, i915, nouveau and radeon support vga_switcheroo. For all other drivers, this change does nothing.",
    "evidence": "osv:CVE-2025-68296",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.143",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.61",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.17.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-68296",
      "aliases": [
        "CVE-2025-68296"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6a9ee8af344e3bd7dbd61e67037096cdf7f83289"
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                {
                  "fixed": "711ebd961190def4c69ea24b2f0be75e995af24a"
                },
                {
                  "fixed": "482330f8261b4bea8146d9bd69c1199e5dfcbb5c"
                },
                {
                  "fixed": "05814c389b53d2f3a0b9eeb90ba7a05ba77c4c2a"
                },
                {
                  "fixed": "eb76d0f5553575599561010f24c277cc5b31d003"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68296.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.34"
                },
                {
                  "fixed": "6.6.143"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.61"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.17.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68296.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.284253414Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/05814c389b53d2f3a0b9eeb90ba7a05ba77c4c2a",
        "https://git.kernel.org/stable/c/482330f8261b4bea8146d9bd69c1199e5dfcbb5c",
        "https://git.kernel.org/stable/c/711ebd961190def4c69ea24b2f0be75e995af24a",
        "https://git.kernel.org/stable/c/eb76d0f5553575599561010f24c277cc5b31d003",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68296.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-68296",
        "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/2025/68xxx/CVE-2025-68296.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-68296",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 494548,
  "published_at": "2025-12-16T15:06:15.797+00:00"
}