Vulnerability-Lookup

CVE-2026-62847 (GCVE-0-2026-62847)

Vulnerability from cvelistv5 – Published: 2026-10-30 20:23 – Updated: 2026-10-30 22:13

Title

Metalama: Local code execution via DLL planting in world-writable temporary directories (Linux/macOS)

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.

Severity

8.2 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-30 21:21 UTC

CWE

CWE-377 - Insecure Temporary File
CWE-427 - Uncontrolled Search Path Element

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 8077 records in the last 180 days details

References

7 references

URL	Tags
https://github.com/metalama/Metalama/security/adv…	x_refsource_CONFIRM
https://github.com/metalama/Metalama/pull/1650	x_refsource_MISC
https://github.com/metalama/Metalama/commit/09911…	x_refsource_MISC
https://github.com/metalama/Metalama/commit/92c4f…	x_refsource_MISC
https://github.com/metalama/Metalama/releases/tag…	x_refsource_MISC
https://github.com/metalama/Metalama/releases/tag…	x_refsource_MISC
https://github.com/metalama/Metalama/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
metalama	Metalama	Affected: < 2025.1.18 Affected: >= 2025.2.0-preview, <= 2025.2.5-rc Affected: >= 2026.0.0-preview, < 2026.0.25 Affected: >= 2026.1.0-preview, < 2026.1.19	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-62847",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-30T21:21:14.933972Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-30T22:13:12.107Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-377",
              "description": "CWE-377: Insecure Temporary File",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-427",
              "description": "CWE-427: Uncontrolled Search Path Element",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T20:23:50.882Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp"
        },
        {
          "name": "https://github.com/metalama/Metalama/pull/1650",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/metalama/Metalama/pull/1650"
        },
        {
          "name": "https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9"
        },
        {
          "name": "https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e"
        },
        {
          "name": "https://github.com/metalama/Metalama/releases/tag/release/2025.1.18",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/metalama/Metalama/releases/tag/release/2025.1.18"
        },
        {
          "name": "https://github.com/metalama/Metalama/releases/tag/release/2026.0.25",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/metalama/Metalama/releases/tag/release/2026.0.25"
        },
        {
          "name": "https://github.com/metalama/Metalama/releases/tag/release/2026.1.19",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/metalama/Metalama/releases/tag/release/2026.1.19"
        }
      ],
      "source": {
        "advisory": "GHSA-m6wq-39m7-9xpp",
        "discovery": "UNKNOWN"
      },
      "title": "Metalama: Local code execution via DLL planting in world-writable temporary directories (Linux/macOS)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-62847",
    "datePublished": "2026-10-30T20:23:50.882Z",
    "dateReserved": "2026-07-14T21:10:50.031Z",
    "dateUpdated": "2026-10-30T22:13:12.107Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-62847",
      "date": "2026-11-01",
      "epss": "0.00151",
      "percentile": "0.04267"
    },
    "nvd": {
      "cve": {
        "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"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-62847",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-10-30T21:21:14.933972Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-10-30T21:21:15.690Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "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"
                }
              ]
            }
          ],
          "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."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "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"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-377",
                  "description": "CWE-377: Insecure Temporary File",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            },
            {
              "descriptions": [
                {
                  "cweId": "CWE-427",
                  "description": "CWE-427: Uncontrolled Search Path Element",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-10-30T20:23:50.882Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp"
            },
            {
              "name": "https://github.com/metalama/Metalama/pull/1650",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/metalama/Metalama/pull/1650"
            },
            {
              "name": "https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9"
            },
            {
              "name": "https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e"
            },
            {
              "name": "https://github.com/metalama/Metalama/releases/tag/release/2025.1.18",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/metalama/Metalama/releases/tag/release/2025.1.18"
            },
            {
              "name": "https://github.com/metalama/Metalama/releases/tag/release/2026.0.25",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/metalama/Metalama/releases/tag/release/2026.0.25"
            },
            {
              "name": "https://github.com/metalama/Metalama/releases/tag/release/2026.1.19",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/metalama/Metalama/releases/tag/release/2026.1.19"
            }
          ],
          "source": {
            "advisory": "GHSA-m6wq-39m7-9xpp",
            "discovery": "UNKNOWN"
          },
          "title": "Metalama: Local code execution via DLL planting in world-writable temporary directories (Linux/macOS)"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-62847",
        "datePublished": "2026-10-30T20:23:50.882Z",
        "dateReserved": "2026-07-14T21:10:50.031Z",
        "dateUpdated": "2026-10-30T22:13:12.107Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

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

References

	URL	Tags
	security-advisories@github.com	https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9
	security-advisories@github.com	https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e
	security-advisories@github.com	https://github.com/metalama/Metalama/pull/1650
	security-advisories@github.com	https://github.com/metalama/Metalama/releases/tag/release/2025.1.18
	security-advisories@github.com	https://github.com/metalama/Metalama/releases/tag/release/2026.0.25
	security-advisories@github.com	https://github.com/metalama/Metalama/releases/tag/release/2026.1.19
	security-advisories@github.com	https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp

Impacted products

	Vendor	Product	Version

JSON

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"
    }
  ]
}

GHSA-M6WQ-39M7-9XPP

Vulnerability from github – Published: 2026-10-14 19:24 – Updated: 2026-10-14 19:24

Summary

Metalama allows local code execution through DLL planting in shared temporary directories

Details

Summary

Metalama loaded and executed compile-time assemblies, auxiliary executable tools, and embedded helper assemblies from predictable temporary directories. On Linux and macOS the default cache location was the world-writable system temporary directory (Path.GetTempPath(), i.e. /tmp), and previously-generated artifacts were trusted based on the presence of a sentinel/.completed marker file rather than on any integrity verification.

A local, unprivileged user on a shared machine or CI/build agent can pre-create the deterministic cache directory structure and plant a malicious DLL together with the matching sentinel file. When a higher-privileged user (or build/service account) subsequently runs a build, Metalama finds the sentinel, skips regeneration, and loads and executes the attacker-supplied assembly inside the compiler / IDE / MSBuild process.

Affected load-and-execute paths: - the cache of compile-time assemblies that Metalama generates from your aspects; - auxiliary executable tools that Metalama extracts to a local directory and then launches; - embedded .NET helper assemblies that Metalama extracts to a local directory and loads into the build / IDE process.

Impact

Arbitrary code execution in the security context of the building user — i.e. a local privilege escalation across user accounts on shared POSIX systems (multi-user developer machines, CI/build agents). The attacker obtains code execution as the victim without holding the victim's privileges, and can read source/secrets, tamper with build output (supply-chain injection), or disrupt builds.

Affected configurations

Linux and macOS, default configuration — affected. The shipped default uses the world-writable system temp directory.
Windows, default configuration — not affected. The default per-user temporary directory is protected by OS ACLs, so cross-user planting is not possible.
The METALAMA_TEMP environment variable is a deployer-controlled override and is out of scope: pointing it at an insecure (e.g. world-writable or attacker-owned) location is a deployment misconfiguration, not a defect in the product.

Severity

CVSS v3.1: AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H = 8.2 (High) for the affected POSIX default configuration (Scope:Changed reflects the cross-user privilege escalation).

CVSS v4.0 cross-check: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:H = 6.0 (Medium), which more granularly attributes low impact to the cache itself and high impact to the subsequent build process. The honest range is therefore Medium-High depending on the scoring model and platform.

Fix

Caches and extraction directories were relocated from the world-writable system temp directory to per-user application-data locations ($XDG_CACHE_HOME / ~/.cache/Metalama on POSIX), relying on OS-enforced per-user ownership as the trust boundary. Fixed in 2026.1.19.

Weaknesses

CWE-377: Insecure Temporary File
CWE-427: Uncontrolled Search Path Element

Affected packages

Metalama.Framework < 2026.1.19,
Metalama.Tool < 2026.1.19

Internal tracking: metalama/Metalama#1650.

Severity

8.2 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

6.0 (Medium)


                  
                    CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Metalama.Framework"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2026.1.0-preview"
            },
            {
              "fixed": "2026.1.19"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Metalama.Tool"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2026.1.0-preview"
            },
            {
              "fixed": "2026.1.19"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Metalama.Framework"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2025.1.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Metalama.Tool"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2025.1.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Metalama.Tool"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2026.0.0-preview"
            },
            {
              "fixed": "2026.0.25"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Metalama.Framework"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2026.0.0-preview"
            },
            {
              "fixed": "2026.0.25"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-62847"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-377",
      "CWE-427"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-14T19:24:53Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nMetalama loaded and executed compile-time assemblies, auxiliary executable tools, and embedded helper assemblies from predictable temporary directories. On Linux and macOS the default cache location was the world-writable system temporary directory (`Path.GetTempPath()`, i.e. `/tmp`), and previously-generated artifacts were trusted based on the presence of a sentinel/`.completed` marker file rather than on any integrity verification.\n\nA local, unprivileged user on a shared machine or CI/build agent can pre-create the deterministic cache directory structure and plant a malicious DLL together with the matching sentinel file. When a higher-privileged user (or build/service account) subsequently runs a build, Metalama finds the sentinel, skips regeneration, and loads and executes the attacker-supplied assembly inside the compiler / IDE / MSBuild process.\n\nAffected load-and-execute paths:\n- the cache of compile-time assemblies that Metalama generates from your aspects;\n- auxiliary executable tools that Metalama extracts to a local directory and then launches;\n- embedded .NET helper assemblies that Metalama extracts to a local directory and loads into the build / IDE process.\n\n## Impact\n\nArbitrary code execution in the security context of the building user \u2014 i.e. a local privilege escalation across user accounts on shared POSIX systems (multi-user developer machines, CI/build agents). The attacker obtains code execution as the victim without holding the victim\u0027s privileges, and can read source/secrets, tamper with build output (supply-chain injection), or disrupt builds.\n\n## Affected configurations\n\n- **Linux and macOS, default configuration \u2014 affected.** The shipped default uses the world-writable system temp directory.\n- **Windows, default configuration \u2014 not affected.** The default per-user temporary directory is protected by OS ACLs, so cross-user planting is not possible.\n- The `METALAMA_TEMP` environment variable is a deployer-controlled override and is **out of scope**: pointing it at an insecure (e.g. world-writable or attacker-owned) location is a deployment misconfiguration, not a defect in the product.\n\n## Severity\n\nCVSS v3.1: `AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H` = **8.2 (High)** for the affected POSIX default configuration (Scope:Changed reflects the cross-user privilege escalation).\n\nCVSS v4.0 cross-check: `CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:H` = 6.0 (Medium), which more granularly attributes low impact to the cache itself and high impact to the subsequent build process. The honest range is therefore Medium-High depending on the scoring model and platform.\n\n## Fix\n\nCaches and extraction directories were relocated from the world-writable system temp directory to per-user application-data locations (`$XDG_CACHE_HOME` / `~/.cache/Metalama` on POSIX), relying on OS-enforced per-user ownership as the trust boundary. Fixed in **2026.1.19**.\n\n## Weaknesses\n\n- CWE-377: Insecure Temporary File\n- CWE-427: Uncontrolled Search Path Element\n\n## Affected packages\n\n- Metalama.Framework \u003c 2026.1.19, \n- Metalama.Tool \u003c 2026.1.19\n\nInternal tracking: metalama/Metalama#1650.",
  "id": "GHSA-m6wq-39m7-9xpp",
  "modified": "2026-10-14T19:24:53Z",
  "published": "2026-10-14T19:24:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/metalama/Metalama/pull/1719"
    },
    {
      "type": "WEB",
      "url": "https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/metalama/Metalama/commit/ab9407263203c66d7c5680a34c28dba31f9951c9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/metalama/Metalama"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Metalama allows local code execution through DLL planting in shared temporary directories"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-62847 (GCVE-0-2026-62847)

FKIE_CVE-2026-62847

GHSA-M6WQ-39M7-9XPP

Summary

Impact

Affected configurations

Severity

Fix

Weaknesses

Affected packages

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour