Vulnerability-Lookup

PYSEC-2026-88

Vulnerability from pysec - Published: 2026-04-23 19:17 - Updated: 2026-05-20 09:19

Details

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.

Severity

7.5 (High)


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

Impacted products

Name	purl
mako	pkg:pypi/mako

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "mako",
        "purl": "pkg:pypi/mako"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.0",
        "0.1.1",
        "0.1.10",
        "0.1.2",
        "0.1.3",
        "0.1.4",
        "0.1.5",
        "0.1.6",
        "0.1.7",
        "0.1.8",
        "0.1.9",
        "0.2.0",
        "0.2.1",
        "0.2.2",
        "0.2.3",
        "0.2.4",
        "0.2.5",
        "0.3.0",
        "0.3.1",
        "0.3.2",
        "0.3.3",
        "0.3.4",
        "0.3.5",
        "0.3.6",
        "0.4.0",
        "0.4.1",
        "0.4.2",
        "0.5.0",
        "0.6.0",
        "0.6.1",
        "0.6.2",
        "0.7.0",
        "0.7.1",
        "0.7.2",
        "0.7.3",
        "0.8.0",
        "0.8.1",
        "0.9.0",
        "0.9.1",
        "1.0.0",
        "1.0.1",
        "1.0.10",
        "1.0.11",
        "1.0.12",
        "1.0.13",
        "1.0.14",
        "1.0.2",
        "1.0.3",
        "1.0.4",
        "1.0.5",
        "1.0.6",
        "1.0.7",
        "1.0.8",
        "1.0.9",
        "1.1.0",
        "1.1.1",
        "1.1.2",
        "1.1.3",
        "1.1.4",
        "1.1.5",
        "1.1.6",
        "1.2.0",
        "1.2.1",
        "1.2.2",
        "1.2.3",
        "1.2.4",
        "1.3.0",
        "1.3.1",
        "1.3.10",
        "1.3.2",
        "1.3.3",
        "1.3.4",
        "1.3.5",
        "1.3.6",
        "1.3.7",
        "1.3.8",
        "1.3.9"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41205",
    "GHSA-v92g-xgxw-vvmm"
  ],
  "details": "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.",
  "id": "PYSEC-2026-88",
  "modified": "2026-05-20T09:19:06.232960Z",
  "published": "2026-04-23T19:17:29.270Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/sqlalchemy/mako/security/advisories/GHSA-v92g-xgxw-vvmm"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-41205 (GCVE-0-2026-41205)

Vulnerability from cvelistv5 – Published: 2026-04-23 18:52 – Updated: 2026-05-20 01:32

Title

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

Summary

Severity

7.7 (High)


                        
                          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

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M

References

3 references

URL	Tags
https://github.com/sqlalchemy/mako/security/advis…	x_refsource_CONFIRM
https://github.com/sqlalchemy/mako/commit/e05ac61…	x_refsource_MISC
https://github.com/sqlalchemy/mako/releases/tag/r…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
sqlalchemy	mako	Affected: < 1.3.11

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-41205",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-23T20:20:51.233790Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-23T20:20:59.107Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "mako",
          "vendor": "sqlalchemy",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.3.11"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-20T01:32:18.382Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sqlalchemy/mako/security/advisories/GHSA-v92g-xgxw-vvmm",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sqlalchemy/mako/security/advisories/GHSA-v92g-xgxw-vvmm"
        },
        {
          "name": "https://github.com/sqlalchemy/mako/commit/e05ac61989a7fb9dd7dcde6cfd72dc48328719a3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sqlalchemy/mako/commit/e05ac61989a7fb9dd7dcde6cfd72dc48328719a3"
        },
        {
          "name": "https://github.com/sqlalchemy/mako/releases/tag/rel_1_3_11",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sqlalchemy/mako/releases/tag/rel_1_3_11"
        }
      ],
      "source": {
        "advisory": "GHSA-v92g-xgxw-vvmm",
        "discovery": "UNKNOWN"
      },
      "title": "Mako: Path traversal via double-slash URI prefix in TemplateLookup"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-41205",
    "datePublished": "2026-04-23T18:52:24.194Z",
    "dateReserved": "2026-04-18T02:51:52.974Z",
    "dateUpdated": "2026-05-20T01:32:18.382Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-V92G-XGXW-VVMM

Vulnerability from github – Published: 2026-04-16 21:16 – Updated: 2026-05-20 01:32

Summary

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

Details

Summary

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:

Template.__init__ strips one leading / using if/slice
TemplateLookup.get_template() strips all leading / using re.sub(r"^\/+", "")

When a URI like //../../../../etc/passwd is passed: 1. get_template() strips all / → ../../../../etc/passwd → file found via posixpath.join(dir_, u) 2. Template.__init__ strips one / → /../../../../etc/passwd → normpath → /etc/passwd 3. /etc/passwd.startswith(..) → False → check bypassed

Impact

Arbitrary file read: any file readable by the process can be returned as rendered template content when an application passes untrusted input directly to TemplateLookup.get_template().

Note: this is exploitable at the library API level. HTTP-based exploitation is mitigated by Python's BaseHTTPRequestHandler which normalizes double-slash prefixes since CPython gh-87389. Applications using other HTTP servers that do not normalize paths may be affected.

Fix

Changed Template.__init__ to use lstrip("/") instead of stripping only a single leading slash, so both code paths handle leading slashes consistently.

Severity

7.5 (High)


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

7.7 (High)


                  
                    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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.3.10"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "Mako"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41205"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T21:16:40Z",
    "nvd_published_at": "2026-04-23T19:17:29Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\n`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:\n\n- `Template.__init__` strips **one** leading `/` using `if`/slice\n- `TemplateLookup.get_template()` strips **all** leading `/` using `re.sub(r\"^\\/+\", \"\")`\n\nWhen a URI like `//../../../../etc/passwd` is passed:\n1. `get_template()` strips all `/` \u2192 `../../../../etc/passwd` \u2192 file found via `posixpath.join(dir_, u)`\n2. `Template.__init__` strips one `/` \u2192 `/../../../../etc/passwd` \u2192 `normpath` \u2192 `/etc/passwd`\n3. `/etc/passwd`.startswith(`..`) \u2192 `False` \u2192 **check bypassed**\n\n### Impact\n\nArbitrary file read: any file readable by the process can be returned as rendered template content when an application passes untrusted input directly to `TemplateLookup.get_template()`.\n\nNote: this is exploitable at the library API level. HTTP-based exploitation is mitigated by Python\u0027s `BaseHTTPRequestHandler` which normalizes double-slash prefixes since CPython gh-87389. Applications using other HTTP servers that do not normalize paths may be affected.\n\n### Fix\n\nChanged `Template.__init__` to use `lstrip(\"/\")` instead of stripping only a single leading slash, so both code paths handle leading slashes consistently.",
  "id": "GHSA-v92g-xgxw-vvmm",
  "modified": "2026-05-20T01:32:53Z",
  "published": "2026-04-16T21:16:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/security/advisories/GHSA-v92g-xgxw-vvmm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41205"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/commit/e05ac61989a7fb9dd7dcde6cfd72dc48328719a3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sqlalchemy/mako"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sqlalchemy/mako/releases/tag/rel_1_3_11"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Mako: Path traversal via double-slash URI prefix in TemplateLookup"
}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

PYSEC-2026-88

CVE-2026-41205 (GCVE-0-2026-41205)

GHSA-V92G-XGXW-VVMM

Summary

Impact

Fix

Tags

Sightings

Nomenclature