GHSA-f54q-j679-p9hh
MEDIUMcopyparty vulnerable to reflected cross-site scripting via k304 parameter
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
copypartyReal-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
The application contains a reflected cross-site scripting via URL-parameter ?k304=... and ?setck=...
Details
A reflected cross-site scripting (XSS) vulnerability exists in the web interface of the application that could allow an attacker to execute malicious javascript code by tricking users into accessing a malicious link.
The worst-case outcome of this is being able to move or delete existing files on the server, or upload new files, using the account of the person who clicks the malicious link.
It is recommended to change the passwords of your copyparty accounts, unless you have inspected your logs and found no trace of attacks.
Checking for exposure
if copyparty is running behind a reverse proxy, you can check the access-logs for traces of attacks, by grepping for URLs containing ?hc= with < somewhere in its value, for example using the following command:
- nginx:
(gzip -dc access.log*.gz; cat access.log) | sed -r 's/" [0-9]+ .*//' | grep -iE '%0[da]%0[da]%0[da]%0[da]|[?&](hc|pw)=.*[<>]'
the above commands also check for attacks against GHSA-cw7j-v52w-fp5r
PoC
https://localhost:3923/?k304=y%0D%0A%0D%0A%3Cimg+src%3Dcopyparty+onerror%3Dalert(1)%3E
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | copyparty | all versions | 1.8.7 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
copyparty v1.8.6 - Reflected Cross Site Scripting (XSS)
by Vartamtezidis Theodoros · Jul 28, 2023
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for copyparty. 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 copyparty to 1.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f54q-j679-p9hh 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-f54q-j679-p9hh 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-f54q-j679-p9hh. 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-f54q-j679-p9hh in your dependencies?
O3 detects GHSA-f54q-j679-p9hh across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.