CVE-2023-32309 is a high-severity (CVSS 7.5) Path Traversal vulnerability in pymdown-extensions. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for pymdown-extensions — see the affected versions and patch details below.
Arbitrary file inclusion with the pymdowm-snippets extension
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-32309.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
pymdown-extensionsReal-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
Arbitrary file read when using include file syntax.
Details
By using the syntax --8<--"/etc/passwd" or --8<--"/proc/self/environ" the content of these files will be rendered in the generated documentation. Additionally, a path relative to a specified, allowed base path can also be used to render the content of a file outside the specified base paths: --8<-- "../../../../etc/passwd".
Within the Snippets extension, there exists a base_path option but the implementation is vulnerable to Directory Traversal.
The vulnerable section exists in get_snippet_path(self, path) lines 155 to 174 in snippets.py.
base = "docs"
path = "/etc/passwd"
filename = os.path.join(base,path) # Filename is now /etc/passwd
PoC
import markdown
payload = "--8<-- \"/etc/passwd\""
html = markdown.markdown(payload, extensions=['pymdownx.snippets'])
print(html)
Impact
Any readable file on the host where the plugin is executing may have its content exposed. This can impact any use of Snippets that exposes the use of Snippets to external users.
It is never recommended to use Snippets to process user-facing, dynamic content. It is designed to process known content on the backend under the control of the host, but if someone were to accidentally enable it for user-facing content, undesired information could be exposed.
Suggestion
Specified snippets should be restricted to the configured, specified base paths as a safe default. Allowing relative or absolute paths that escape the specified base paths would need to be behind a feature switch that must be opt-in and would be at the developer's own risk.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pymdown-extensions | ≥ 1.5&&< 10.0 | 10.0pip install --upgrade 'pymdown-extensions==10.0' |
Affected Products
pymdown extensionsfacelessuserResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pymdown-extensions, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pymdown-extensions to 10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-32309 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2023-32309 in your dependencies?
Find it across PyPI, including transitive dependencies.