Vector: Arbitrary file write in the file sink via templated path (path traversal).

{
  "id": "777527a2d33cab7db1d47dd98782a597e7469cf635dc7b5c4b3314a162f7cb01",
  "url": "https://osv.dev/vulnerability/CVE-2026-77621",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Vector: Arbitrary file write in the file sink via templated path (path traversal).",
    "summary": "Vector is a high-performance observability data pipeline. From 0.10.0 until 0.57.0, the file sink renders its templated path from event fields and opens the result without confining it to an intended directory. When an untrusted source supplies an event field used by the path template, the value can contain an absolute path or parent-directory traversal, causing Vector to create parent directories and create or overwrite files outside the intended location with the Vector process privileges. The resulting file write can modify sensitive files and can lead to code execution when a scheduled task, authorization file, or subsequently executed script is targeted. This issue is fixed in version 0.57.0.",
    "evidence": "osv:CVE-2026-77621",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-77621",
      "aliases": [
        "CVE-2026-77621",
        "GHSA-6342-xwvw-c637"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/vectordotdev/vector",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0f0311aebc4124eb06759633f4d4a9f098b36f07"
                },
                {
                  "fixed": "8832452f57afb536ea0de53a093f9fd1b669ccec"
                },
                {
                  "fixed": "6951064ed1d295fbff67a5ba7da5971fc6f58c46"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.10.0"
                      },
                      {
                        "fixed": "0.57.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "6951064ed1d295fbff67a5ba7da5971fc6f58c46"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8832452f57afb536ea0de53a093f9fd1b669ccec"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8832452f57afb536ea0de53a093f9fd1b669ccec"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.57.0"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-77621.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.486702448Z",
      "provider": "osv",
      "references": [
        "https://github.com/vectordotdev/vector/releases/tag/v0.57.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77621.json",
        "https://github.com/vectordotdev/vector/security/advisories/GHSA-6342-xwvw-c637",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-77621",
        "https://github.com/vectordotdev/vector/commit/6951064ed1d295fbff67a5ba7da5971fc6f58c46",
        "https://github.com/vectordotdev/vector/commit/8832452f57afb536ea0de53a093f9fd1b669ccec",
        "https://github.com/vectordotdev/vector/pull/25820",
        "https://github.com/vectordotdev/vector/pull/25830"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22",
          "CWE-73"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77621.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-77621",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517985,
  "published_at": "2026-09-22T15:19:19.526+00:00"
}