CVE-2026-44307 Mako: Path traversal via backslash URI on Windows in TemplateLookup
An attacker can read arbitrary files outside the template directory on Windows by using backslash traversal in URIs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44307?
CVE-2026-44307 is a high-severity path traversal vulnerability in sqlalchemy mako, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-22
Which versions are affected by CVE-2026-44307?
3 open source packages ship an affected version, including mako and Mako.
| Package | Affected | Fixed in |
|---|---|---|
mako PyPI | All versions | 1.3.12 |
mako PyPI | All versions | 1.3.12 |
Mako PyPI | All versions | 1.3.12 |
How do I fix CVE-2026-44307?
Upgrade mako to 1.3.12 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-44307 being exploited?
There is no known exploitation of CVE-2026-44307 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-AF49322, CLEANSTART-2026-MF83934, ECHO-15a8-1150-dd0d, GHSA-2h4p-vjrc-8xpq, MINI-3hf9-jwj9-rr54, MINI-7xgp-g26j-67f7 and 6 more.