FKIE_CVE-2026-62847

Vulnerability from fkie_nvd - Published: 2026-10-30 21:17 - Updated: 2026-10-30 23:17
Severity
8.2 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Summary
Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. Prior to 2025.1.18, 2026.0.25 and 2026.1.19, Metalama.Framework and Metalama.Tool load and execute compile-time assemblies, auxiliary executable tools and embedded helper assemblies from predictable temporary directories. On `Linux` and `macOS`, the default `Path.GetTempPath()` location is world-writable, and existing artifacts are trusted based on sentinel or `.completed` marker files rather than integrity verification. A local unprivileged user on a shared machine or CI/build agent can pre-create the deterministic directory structure and plant a malicious DLL with the matching sentinel. When a higher-privileged developer or build account subsequently builds, Metalama skips regeneration and executes the planted artifact in the compiler, IDE or MSBuild process as the building user. This permits cross-user privilege escalation, reading source and secrets, supply-chain tampering with build output, or disrupting builds. Default Windows per-user temporary directories are protected by ACLs and are not affected. Deployer-selected insecure cache locations are outside the vulnerability's scope. This issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19.
References
security-advisories@github.comhttps://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9
security-advisories@github.comhttps://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e
security-advisories@github.comhttps://github.com/metalama/Metalama/pull/1650
security-advisories@github.comhttps://github.com/metalama/Metalama/releases/tag/release/2025.1.18
security-advisories@github.comhttps://github.com/metalama/Metalama/releases/tag/release/2026.0.25
security-advisories@github.comhttps://github.com/metalama/Metalama/releases/tag/release/2026.1.19
security-advisories@github.comhttps://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Metalama",
          "vendor": "metalama",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2025.1.18"
            },
            {
              "status": "affected",
              "version": "\u003e= 2025.2.0-preview, \u003c= 2025.2.5-rc"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.0.0-preview, \u003c 2026.0.25"
            },
            {
              "status": "affected",
              "version": "\u003e= 2026.1.0-preview, \u003c 2026.1.19"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. Prior to 2025.1.18, 2026.0.25 and 2026.1.19, Metalama.Framework and Metalama.Tool load and execute compile-time assemblies, auxiliary executable tools and embedded helper assemblies from predictable temporary directories. On `Linux` and `macOS`, the default `Path.GetTempPath()` location is world-writable, and existing artifacts are trusted based on sentinel or `.completed` marker files rather than integrity verification. A local unprivileged user on a shared machine or CI/build agent can pre-create the deterministic directory structure and plant a malicious DLL with the matching sentinel. When a higher-privileged developer or build account subsequently builds, Metalama skips regeneration and executes the planted artifact in the compiler, IDE or MSBuild process as the building user. This permits cross-user privilege escalation, reading source and secrets, supply-chain tampering with build output, or disrupting builds. Default Windows per-user temporary directories are protected by ACLs and are not affected. Deployer-selected insecure cache locations are outside the vulnerability\u0027s scope. This issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19."
    }
  ],
  "id": "CVE-2026-62847",
  "lastModified": "2026-10-30T23:17:12.923",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.5,
        "impactScore": 6.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-62847",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-30T21:21:14.933972Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-30T21:17:13.807",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/pull/1650"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/releases/tag/release/2025.1.18"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/releases/tag/release/2026.0.25"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/releases/tag/release/2026.1.19"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-377"
        },
        {
          "lang": "en",
          "value": "CWE-427"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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