GHSA-ch22-x2v3-v6vq
HIGHOTF-001: Improper Input Sanitation: The path parameter of the requested URL is not sanitized before being passed to the QT frontend
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.
Blast Radius
onionshare-cliReal-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
Between September 26, 2021 and October 8, 2021, Radically Open Security conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's Red Team lab. This is an issue from that penetration test.
- Vulnerability ID: OTF-001
- Vulnerability type: Improper Input Sanitization
- Threat level: Elevated
Description:
The path parameter of the requested URL is not sanitized before being passed to the QT frontend.
Technical description:
The path parameter is not sanitized before being passed to the constructor of the QLabel.
https://doc.qt.io/qt-5/qlabel.html#details
Warning: When passing a QString to the constructor or calling setText(), make sure to sanitize your input, as QLabel tries to guess whether it displays the text as plain text or as rich text, a subset of HTML 4 markup. You may want to call setTextFormat() explicitly, e.g. in case you expect the text to be in plain format but cannot control the text source (for instance when displaying data loaded from the Web).
This path is used in all components for displaying the server access history. This leads to a rendered HTML4 Subset (QT RichText editor) in the Onionshare frontend.
In the following example an adversary injects a crafted image file into an Onionshare instance with receive mode and renders it in the history component of the Onionshare application.
The only requirement is another visit to the shared site with the following parameter attached to the path of the URL:
<img src='data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAIAAAACUFjqAAAAFElEQVQY02Nk+M+ABzAxMIxKYwIAQC0BEwZFOw4AAAAASUVORK5CYII=' />
This will be rendered as a green square in the history tab where the path value is supposed to be (the value itself is shown at the bottom of the page).
Possible scenarios where this could lead to remote code execution would be a 0-day in libpng or other internal image rendering (OTF-014 (page 12)) of the QT framework.
The QT documentation indicates that external files could be rendered, but we were unable to find a QT code path allowing for it.
Impact:
An adversary with knowledge of the Onion service address in public mode or with authentication in private mode can render arbitrary HTML (QT-HTML4 Subset) in the server desktop application. This requires the desktop application with rendered history, therefore the impact is only elevated.
Recommendation:
- Manually define the text format of the QLabel via
setTextFormat()
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | onionshare-cli | all versions | 2.5 |
Research 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 onionshare-cli. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update onionshare-cli to 2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-ch22-x2v3-v6vq 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 pinpoints whether GHSA-ch22-x2v3-v6vq is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-ch22-x2v3-v6vq. 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-ch22-x2v3-v6vq in your dependencies?
O3 detects GHSA-ch22-x2v3-v6vq across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.