GHSA-v92g-xgxw-vvmm is a high-severity (CVSS 7.5) Path Traversal vulnerability in mako. A fix is available for mako — see the affected versions and patch details below.
Mako: Path traversal via double-slash URI prefix in TemplateLookup
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-v92g-xgxw-vvmm.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-v92g-xgxw-vvmm plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
makoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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:
Template.__init__strips one leading/usingif/sliceTemplateLookup.get_template()strips all leading/usingre.sub(r"^\/+", "")
When a URI like //../../../../etc/passwd is passed:
get_template()strips all/→../../../../etc/passwd→ file found viaposixpath.join(dir_, u)Template.__init__strips one/→/../../../../etc/passwd→normpath→/etc/passwd/etc/passwd.startswith(..) →False→ check bypassed
Impact
Arbitrary file read: any file readable by the process can be returned as rendered template content when an application passes untrusted input directly to TemplateLookup.get_template().
Note: this is exploitable at the library API level. HTTP-based exploitation is mitigated by Python's BaseHTTPRequestHandler which normalizes double-slash prefixes since CPython gh-87389. Applications using other HTTP servers that do not normalize paths may be affected.
Fix
Changed Template.__init__ to use lstrip("/") instead of stripping only a single leading slash, so both code paths handle leading slashes consistently.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | mako | all versions | 1.3.11pip install --upgrade 'mako==1.3.11' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mako, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mako to 1.3.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v92g-xgxw-vvmm is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-v92g-xgxw-vvmm can be triaged on real exposure rather than presence alone.
Tailored to GHSA-v92g-xgxw-vvmm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-v92g-xgxw-vvmm in your dependencies?
O3 Security finds GHSA-v92g-xgxw-vvmm across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.