CVE-2026-63855

Status: Awaiting AnalysisHigh (7.8)—

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

drm/amdgpu/vcn: set no_user_fence for VCN v2.5 enc/dec rings

VCN encoder and decoder rings do not support 64-bit user fence writes, reject CS submissions with user fences.

(cherry picked from commit efc9dd5590894109bce9a0bfe1fa5592dd6b20b1)

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.18%
Percentile among all scored CVEs: 6
Score date: 10/6/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Primary impactT1059 Command and Scripting Interpreterexecution60 %
Secondary impactT1499.004 Application or System Exploitationimpact50 %

AV:L + PR:L + UI:N → T1068. Falta de validación en anillos VCN permite escalada desde usuario local. Impactos: ejecución de código arbitrario o DoS en controlador gráfico.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Execution Prevention Threat Intelligence Program Restrict Web-Based Content Privileged Account Management Limit Software Installation Filter Network Traffic

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux Kernel^AI

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-63855",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
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      "affectedData": [
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          "versions": [
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              "versionType": "git"
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          "programFiles": [
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          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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          "versions": [
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              "status": "affected",
              "version": "5.4"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.4",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.141",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.91",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver",
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            },
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              "version": "7.0.10",
              "versionType": "semver",
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              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c"
          ],
          "defaultStatus": "affected"
        }
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  ],
  "published": "2026-07-19T15:16:52.337",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/2c6fb056567efb49f8674108b86088a1cfaa86d0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu/vcn: set no_user_fence for VCN v2.5 enc/dec rings\n\nVCN encoder and decoder rings do not support 64-bit user fence writes,\nreject CS submissions with user fences.\n\n(cherry picked from commit efc9dd5590894109bce9a0bfe1fa5592dd6b20b1)"
    }
  ],
  "lastModified": "2026-07-27T17:44:23.777",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}