CVE-2024-39918 is a medium-severity (CVSS 4.3) Path Traversal vulnerability in @jmondi/url-to-png. A fix is available for @jmondi/url-to-png — see the affected versions and patch details below.
Path Traveral in @jmondi/url-to-png
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.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-39918.
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
CVE-2024-39918 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 378,567 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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@jmondi/url-to-pngnpmDescription
Summary
When trying to add a BLOCK_LIST feature when the maintainer noticed they didn't sanitize the ImageId in the code, which leads to path traversal vulnerability. Now, this is different from a traditional path traversal issue, because as of NOW you can store the image in any place arbitrarily, and given enough time they might be able to come up with a working exploit BUT for the time being they am reporting this.
Details
@jmondi/url-to-png does not sanitizing the ImageID as in not removing special chars from the params (extract_query_params.ts#l75)
const imageId = dateString + "." + slugify(validData.url) +configToString(params);
This when fed to other parts of the code such as (filesystem.ts#L34)
return path.join(this.storagePath, imageId) + ".png";
Would result in path traversal issue.
PoC
# Configuration for filesystem storage provider (optional)
STORAGE_PROVIDER=filesystem
IMAGE_STORAGE_PATH=poc
Set this in your .env file and use this as your payload.
http://localhost:3089/?url=http://example.com&width=400&isDarkMode=../../../../../../../../../../../../tmp/hack
This will create a .png file in the /tmp section of the system.
Loom POC: https://www.loom.com/share/bd7b306cdae7445c97e68f0626e743a6
This is valid for pretty much all the arguments (except for numeric values)
A simple fix would be to use the slugify for the params as well like so (#L75)
- const imageId = dateString + "." + slugify(validData.url) + configToString(params);
+ const imageId = dateString + "." + slugify(validData.url) + slugify(configToString(params));
Impact
This would be path traversal vulnerability which allows arbitrary write as of now.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @jmondi/url-to-png | all versions | 2.1.2npm install @jmondi/url-to-png@2.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @jmondi/url-to-png, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @jmondi/url-to-png to 2.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-39918 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 CVE-2024-39918 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-39918. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-39918 in your dependencies?
O3 Security finds CVE-2024-39918 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.