CVE-2026-98786 (GCVE-0-2026-98786)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:48 – Updated: 2026-10-19 09:25
VLAI
Title
drm/amd/display: guard dc_sink dereferences in MST mode validation
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: guard dc_sink dereferences in MST mode validation dm_dp_mst_is_port_support_mode() reads aconnector->dc_sink->dsc_caps... for the DSC branch-throughput check, and get_conv_frl_bw()'s HDMI-PCON FRL-bandwidth path reads aconnector->dc_sink->edid_caps.max_frl_rate, both without a NULL check. dc_sink is cleared asynchronously on MST unplug, and both functions run from paths that the driver's own comments document as racing that teardown: the connector probe worker's ->mode_valid callback and a compositor's atomic check, neither of which holds the MST manager lock that the teardown path uses. The former does have an existing dsc_aux NULL check, but dsc_aux isn't reliably cleared in every path that clears dc_sink, so it doesn't cover this. Fail the port-support check and skip the FRL conversion path when the sink is already gone. (cherry picked from commit 7c3db8da4e039698ae198c870712428644e965c7)
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7018 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f04d275d94e164d24516c32437c988a323018f63 , < daa0437fe5e451856aaf8fda602a9fc2105bbd54 (git)
Affected: f04d275d94e164d24516c32437c988a323018f63 , < 217f64f348c90cba62164e7ff38e0ccf78a5ca09 (git)
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Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 7.2.10 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c"
          ],
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: guard dc_sink dereferences in MST mode validation\n\ndm_dp_mst_is_port_support_mode() reads\naconnector-\u003edc_sink-\u003edsc_caps... for the DSC branch-throughput check,\nand get_conv_frl_bw()\u0027s HDMI-PCON FRL-bandwidth path reads\naconnector-\u003edc_sink-\u003eedid_caps.max_frl_rate, both without a NULL\ncheck. dc_sink is cleared asynchronously on MST unplug, and both\nfunctions run from paths that the driver\u0027s own comments document as\nracing that teardown: the connector probe worker\u0027s -\u003emode_valid\ncallback and a compositor\u0027s atomic check, neither of which holds the\nMST manager lock that the teardown path uses. The former does have an\nexisting dsc_aux NULL check, but dsc_aux isn\u0027t reliably cleared in\nevery path that clears dc_sink, so it doesn\u0027t cover this.\n\nFail the port-support check and skip the FRL conversion path when the\nsink is already gone.\n\n(cherry picked from commit 7c3db8da4e039698ae198c870712428644e965c7)"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:25:39.296Z",
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        "shortName": "Linux"
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    "datePublished": "2026-10-18T15:48:22.989Z",
    "dateReserved": "2026-09-25T10:25:14.370Z",
    "dateUpdated": "2026-10-19T09:25:39.296Z",
    "state": "PUBLISHED"
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      "product_status:known_affected": "1",
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      "version": "2"
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          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: guard dc_sink dereferences in MST mode validation\n\ndm_dp_mst_is_port_support_mode() reads\naconnector-\u003edc_sink-\u003edsc_caps... for the DSC branch-throughput check,\nand get_conv_frl_bw()\u0027s HDMI-PCON FRL-bandwidth path reads\naconnector-\u003edc_sink-\u003eedid_caps.max_frl_rate, both without a NULL\ncheck. dc_sink is cleared asynchronously on MST unplug, and both\nfunctions run from paths that the driver\u0027s own comments document as\nracing that teardown: the connector probe worker\u0027s -\u003emode_valid\ncallback and a compositor\u0027s atomic check, neither of which holds the\nMST manager lock that the teardown path uses. The former does have an\nexisting dsc_aux NULL check, but dsc_aux isn\u0027t reliably cleared in\nevery path that clears dc_sink, so it doesn\u0027t cover this.\n\nFail the port-support check and skip the FRL conversion path when the\nsink is already gone.\n\n(cherry picked from commit 7c3db8da4e039698ae198c870712428644e965c7)"
          }
        ],
        "id": "CVE-2026-98786",
        "lastModified": "2026-10-19T10:19:42.693",
        "metrics": {},
        "published": "2026-10-18T16:17:32.580",
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      "title": "kernel: drm/amd/display: guard dc_sink dereferences in MST mode validation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98786.json",
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}



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