CVE-2026-102991

6.5 MEDIUM 0.4% exploit odds Fix listed Disclosure Library

What it is

Mako is a template library written in Python. Prior to 1.4.2, on Windows, TemplateLookup.get_template() in mako/lookup.py resolves template URIs with posixpath, while Template.__init__() in mako/template.py validates them with os.path, which uses ntpath. A URI beginning with a drive designator causes ntpath to absorb the traversal segments before the leading dot-dot check, while posixpath resolution can escape the configured template directory. An application that passes attacker-controlled template names or include paths can disclose process-readable files on the same volume, and a targeted file containing Mako template syntax may also be parsed and executed as a template. Raw URL paths are generally normalized before reaching this form, but query strings, form or JSON bodies, route parameters, and dynamic include expressions can preserve it. This issue is fixed in version 1.4.2.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-09-30 20:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-30 20:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 6.5 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-09-30 20:17 UTC
Last modified: 2026-09-30 20:17 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-22 · Path traversal
Record status: Deferred

Attack profile CVSS 3.1 · 6.5

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: Low
Availability: None

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-102991.md and follow it. Check whether this project is affected by CVE-2026-102991. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

· More options · Status badge

Download Square Reddit

Fix and advisories

References

NVD record · CVE.org record