Mako: Path traversal via double-slash URI prefix in TemplateLookup

{
  "id": "cc4633f803b3ca44009be89b27ae9a89bd3ac556bfd966d3507b4a9a5168d114",
  "url": "https://osv.dev/vulnerability/CVE-2026-41205",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Mako: Path traversal via double-slash URI prefix in TemplateLookup",
    "summary": "Mako is a template library written in Python. Prior to 1.3.11, TemplateLookup.get_template() is vulnerable to path traversal when a URI starts with // (e.g., //../../../secret.txt). The root cause is an inconsistency between two slash-stripping implementations. Any file readable by the process can be returned as rendered template content when an application passes untrusted input directly to TemplateLookup.get_template(). This vulnerability is fixed in 1.3.11.",
    "evidence": "osv:CVE-2026-41205",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-41205",
      "aliases": [
        "CVE-2026-41205",
        "GHSA-v92g-xgxw-vvmm",
        "PYSEC-2026-88"
      ],
      "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/E:P"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/sqlalchemy/mako",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "217822b548fdf9fd730b2f3c1f1e770d4c816df9"
                },
                {
                  "fixed": "e05ac61989a7fb9dd7dcde6cfd72dc48328719a3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:sqlalchemy:mako:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.3.11"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e05ac61989a7fb9dd7dcde6cfd72dc48328719a3"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "217822b548fdf9fd730b2f3c1f1e770d4c816df9"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "rel_1_3_11"
                  }
                ]
              }
            }
          ],
          "versions": [
            "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-2026-41205.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:35.822899313Z",
      "provider": "osv",
      "references": [
        "https://github.com/sqlalchemy/mako/releases/tag/rel_1_3_11",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41205.json",
        "https://github.com/sqlalchemy/mako/security/advisories/GHSA-v92g-xgxw-vvmm",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-41205",
        "https://github.com/sqlalchemy/mako/commit/e05ac61989a7fb9dd7dcde6cfd72dc48328719a3"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41205.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-41205",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 503211,
  "published_at": "2026-04-23T18:52:24.194+00:00"
}