CVE-2026-102991

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (27th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 6.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
45
EG Risk 45/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
27th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 30, 2026

Last Modified

September 30, 2026

Advisory Details (4)

Auto-updated Sep 30, 2026
Patch available. Sources: github, github_commit, github_release.
github Patch Available

Path traversal via drive-letter URI on Windows in TemplateLookup · Advisory · sqlalchemy/mako · GitHub

https://github.com/sqlalchemy/mako/security/advisories/GHSA-5639-2j2p-m4mx
github_release Patch Available

1.4.2

Patch available: sqlalchemy/mako rel_1_4_2

https://github.com/sqlalchemy/mako/releases/tag/rel_1_4_2
generic

drive designator handling issue in template URI normalization on Windows · Issue #441 · sqlalchemy/mako · GitHub

https://github.com/sqlalchemy/mako/issues/441
github_commit Patch Available

commit 000ed85e4e48 (sqlalchemy/mako)

Patch available: sqlalchemy/mako rel_1_4_2 (contains commit 000ed85e4e48)

https://github.com/sqlalchemy/mako/commit/000ed85e4e48771eff460bf4fc721fb43de80e08

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 9× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 02:26 UTCEG score recompute
  2. 2026-10-03 14:25 UTCEPSS rescore
  3. 2026-10-03 00:26 UTCEG score recompute
  4. 2026-10-01 22:25 UTCEG score recompute
  5. 2026-10-01 19:49 UTCEPSS rescore
  6. 2026-09-30 20:22 UTCEG score recompute
  7. 2026-09-30 19:56 UTCEG score recompute
  8. 2026-09-30 19:51 UTCEG score recompute
  9. 2026-09-30 19:50 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-102991?
CVE-2026-102991 is a medium vulnerability published on September 30, 2026. 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…
When was CVE-2026-102991 disclosed?
CVE-2026-102991 was first published on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-102991 actively exploited?
CVE-2026-102991 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (27th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102991?
CVE-2026-102991 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-102991?
A fix for CVE-2026-102991 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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