Mako: Path traversal via double-slash URI prefix in TemplateLookup
CVE-2026-41205 is fixed in 3 products on 1 platform, first by python3-mako 1.3.10-3ubuntu0.1, released April 23, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| python-mako · Ubuntu 18.04.6 LTS (bionic) | 1.0.7+ds1-1ubuntu0.2+esm1 | python-mako 1.0.7+ds1-1ubuntu0.2+esm1 | May 15, 2026 |
| python-mako · Ubuntu 20.04 LTS (focal) | 1.1.0+ds1-1ubuntu2.1+esm1 | python-mako 1.1.0+ds1-1ubuntu2.1+esm1 | May 15, 2026 |
| python-mako-doc · amzn 2023 | 1.1.4-3.amzn2023.0.4 | ALAS2023-2026-1846 | Jun 22, 2026 |
| python3-mako · Ubuntu 18.04.6 LTS (bionic) | 1.0.7+ds1-1ubuntu0.2+esm1 | python3-mako 1.0.7+ds1-1ubuntu0.2+esm1 | May 15, 2026 |
| python3-mako · Ubuntu 20.04 LTS (focal) | 1.1.0+ds1-1ubuntu2.1+esm1 | python3-mako 1.1.0+ds1-1ubuntu2.1+esm1 | May 15, 2026 |
| python3-mako · Ubuntu 22.04.1 LTS (jammy) | 1.1.3+ds1-2ubuntu0.2 | python3-mako 1.1.3+ds1-2ubuntu0.2 | May 15, 2026 |
| python3-mako · Ubuntu 24.04.5 LTS (noble) | 1.3.2-1ubuntu0.1 | python3-mako 1.3.2-1ubuntu0.1 | May 15, 2026 |
| python3-mako · Ubuntu 25.10 (questing) | 1.3.9-1ubuntu0.1 | python3-mako 1.3.9-1ubuntu0.1 | May 15, 2026 |
| python3-mako · Ubuntu 26.04.1 LTS (resolute) | 1.3.10-3ubuntu0.1 | python3-mako 1.3.10-3ubuntu0.1 | Apr 23, 2026 |
| python3-mako · amzn 2023 | 1.1.4-3.amzn2023.0.4 | ALAS2023-2026-1846 | Jun 22, 2026 |
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