FKIE_CVE-2026-68235

Vulnerability from fkie_nvd - Published: 2026-08-10 13:20 - Updated: 2026-08-18 07:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: dce100: skip non-DP stream encoders for DP MST On DCE8-class ASICs (e.g. Bonaire), the resource pool contains digital DIG stream encoders plus one analog DAC encoder. When assigning a stream encoder for a second DisplayPort MST stream, if the preferred digital encoder is already acquired, dce100_find_first_free_match_stream_enc_for_link() falls back to the first free pool entry. That entry may be the analog encoder, whose funcs table lacks DP hooks such as dp_set_stream_attribute. The subsequent atomic commit then dereferences NULL function pointers in link_set_dpms_on() and crashes. Skip encoders without dp_set_stream_attribute when the stream uses a DP signal (including MST). Use dc_is_dp_signal(stream->signal) for the MST fallback path instead of checking only the link connector signal. Tested on: - GPU: AMD Radeon R7 260X (Bonaire / DCE8) - Board: Supermicro C9X299-PG300 - Setup: DP MST daisy chain, hotplug second monitor or have it connected on boot - Kernel: 7.1.3 (issue observed since 6.19) - Result: kernel oops without patch; dual monitors stable with patch (cherry picked from commit 28ec64943e3ee4d9b8d30cea61e380f1429953a8)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d340cba0df4cf327c7e89c7c1a4e79d4771d7dd5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ed2d86aef9fa4c43f82da0fca91a60f7326d7d03
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resource.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ed2d86aef9fa4c43f82da0fca91a60f7326d7d03",
              "status": "affected",
              "version": "5834c33fd3f6f2a26dd4d6d4bbc7b8ed1c2ac4aa",
              "versionType": "git"
            },
            {
              "lessThan": "d340cba0df4cf327c7e89c7c1a4e79d4771d7dd5",
              "status": "affected",
              "version": "5834c33fd3f6f2a26dd4d6d4bbc7b8ed1c2ac4aa",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resource.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: dce100: skip non-DP stream encoders for DP MST\n\nOn DCE8-class ASICs (e.g. Bonaire), the resource pool contains digital\nDIG stream encoders plus one analog DAC encoder. When assigning a stream\nencoder for a second DisplayPort MST stream, if the preferred digital\nencoder is already acquired, dce100_find_first_free_match_stream_enc_for_link()\nfalls back to the first free pool entry. That entry may be the analog\nencoder, whose funcs table lacks DP hooks such as dp_set_stream_attribute.\nThe subsequent atomic commit then dereferences NULL function pointers in\nlink_set_dpms_on() and crashes.\n\nSkip encoders without dp_set_stream_attribute when the stream uses a DP\nsignal (including MST). Use dc_is_dp_signal(stream-\u003esignal) for the MST\nfallback path instead of checking only the link connector signal.\n\nTested on:\n- GPU: AMD Radeon R7 260X (Bonaire / DCE8)\n- Board: Supermicro C9X299-PG300\n- Setup: DP MST daisy chain, hotplug second monitor or have it connected on boot\n- Kernel: 7.1.3 (issue observed since 6.19)\n- Result: kernel oops without patch; dual monitors stable with patch\n\n(cherry picked from commit 28ec64943e3ee4d9b8d30cea61e380f1429953a8)"
    }
  ],
  "id": "CVE-2026-68235",
  "lastModified": "2026-08-18T07:16:50.750",
  "metrics": {},
  "published": "2026-08-10T13:20:11.827",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d340cba0df4cf327c7e89c7c1a4e79d4771d7dd5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ed2d86aef9fa4c43f82da0fca91a60f7326d7d03"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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