Mako: Path traversal via drive-letter URI on Windows in TemplateLookup (CVE-2026-102991) | HOL Guard CVE

Medium · CVSS 6.5CVE-2026-102991

Mako: Path traversal via drive-letter URI on Windows in TemplateLookup

Answer in brief

CVE-2026-102991 records a Medium severity (CVSS 6.5) vulnerability in Mako: Path traversal via drive-letter URI on Windows in TemplateLookup. The current sources do not mark it as known exploited. The current feed maps sqlalchemy/mako (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 30, 2026Updated Sep 30, 2026Source checked Sep 30, 2026First seen by HOL Sep 30, 2026Material review Sep 30, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps sqlalchemy/mako (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
sqlalchemy/makogeneric	<1.4.2	1.4.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for sqlalchemy/mako.
Review the reported fix. Update sqlalchemy/mako to 1.4.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 30, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.