Mako: Path traversal via backslash URI on Windows in TemplateLookup

{
  "id": "e75faf643e4d0ee0b5bdc72a7f55be71b947f96f54f734bb192af8c5cdb61e90",
  "url": "https://osv.dev/vulnerability/CVE-2026-44307",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Mako: Path traversal via backslash URI on Windows in TemplateLookup",
    "summary": "Mako is a template library written in Python. Prior to 1.3.12, on Windows, a URI using backslash traversal (e.g. \\..\\..\\ secret.txt) bypasses the directory traversal check in Template.__init__ and the posixpath-based normalization in TemplateLookup.get_template(), allowing reads of files outside the configured template directory. This vulnerability is fixed in 1.3.12.",
    "evidence": "osv:CVE-2026-44307",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-44307",
      "aliases": [
        "CVE-2026-44307",
        "GHSA-2h4p-vjrc-8xpq",
        "PYSEC-2026-2617"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/sqlalchemy/mako",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "d4d1639222d2da4f18c32d11f32c37f172f603bd"
                },
                {
                  "fixed": "72e10c573ca0fbcbddd4455abca8ce92a61780d7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.3.12"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "72e10c573ca0fbcbddd4455abca8ce92a61780d7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d4d1639222d2da4f18c32d11f32c37f172f603bd"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "rel_1_3_12"
                  }
                ]
              }
            }
          ],
          "versions": [
            "rel_1_3_11",
            "rel_1_3_10",
            "rel_1_3_9",
            "rel_1_3_8",
            "rel_1_3_7",
            "rel_1_3_6",
            "rel_1_3_5",
            "rel_1_3_4",
            "rel_1_3_3",
            "rel_1_3_2",
            "rel_1_3_1",
            "rel_1_3_0",
            "rel_1_2_4",
            "rel_1_2_3",
            "rel_1_2_2",
            "rel_1_2_1",
            "rel_1_2_0",
            "rel_1_1_5",
            "rel_1_1_4",
            "rel_1_1_3",
            "rel_1_1_2",
            "rel_1_1_1",
            "rel_1_1_0",
            "rel_1_0_14",
            "rel_1_0_13",
            "rel_1_0_12",
            "rel_1_0_11",
            "rel_1_0_10",
            "rel_1_0_9",
            "rel_1_0_8",
            "rel_1_0_7",
            "rel_1_0_6",
            "rel_1_0_5",
            "rel_1_0_4",
            "rel_1_0_3",
            "rel_1_0_2",
            "rel_1_0_1",
            "rel_1_0_0",
            "rel_0_9_1",
            "rel_0_9_0",
            "rel_0_8_1",
            "rel_0_8_0",
            "rel_0_7_3",
            "rel_0_7_2",
            "rel_0_7_1",
            "rel_0_7_0",
            "rel_0_6_2",
            "rel_0_6_1",
            "rel_0_6_0",
            "rel_0_5_0",
            "rel_0_4_2",
            "rel_0_4_1",
            "rel_0_4_0",
            "rel_0_3_6",
            "rel_0_3_5",
            "rel_0_3_4",
            "rel_0_3_3",
            "rel_0_3_2",
            "rel_0_3_1",
            "rel_0_3_0",
            "rel_0_2_5",
            "rel_0_2_4",
            "rel_0_2_3",
            "rel_0_2_2",
            "rel_0_2_1",
            "rel_0_2_0",
            "rel_0_1_10",
            "rel_0_1_9",
            "rel_0_1_8",
            "rel_0_1_7",
            "rel_0_1_6",
            "rel_0_1_5",
            "rel_0_1_4",
            "rel_0_1_3",
            "rel_0_1_2",
            "rel_0_1_1",
            "rel_0_1_0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44307.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:31.367611477Z",
      "provider": "osv",
      "references": [
        "https://github.com/sqlalchemy/mako/releases/tag/rel_1_3_12",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44307.json",
        "https://github.com/sqlalchemy/mako/security/advisories/GHSA-2h4p-vjrc-8xpq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44307",
        "https://github.com/sqlalchemy/mako/issues/435",
        "https://github.com/sqlalchemy/mako/commit/72e10c573ca0fbcbddd4455abca8ce92a61780d7"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44307.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44307",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 498114,
  "published_at": "2026-05-12T21:53:52.826+00:00"
}