CVE-2026-48484 is a medium-severity (CVSS 6.5) Improper Input Validation vulnerability in pyload-ng. A fix is available for pyload-ng — see the affected versions and patch details below.
pyLoad: Lack of Input Size Validation Leads to Denial of Service (DoS) and Process Termination
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-2026-48484.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-48484 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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
Description:
The API rpc function in api_blueprint.py handles multipart/form-data uploads by reading the whole content of the uploaded file into memory with file.read(). This occurs before the data is sent to the underlying function. Since there is no size limit set at this point, a large file upload can exhaust the server's available memory which led to process termination.
VulnerableCode & Path:
Steps to Reproduce:
- Log in to pyLoad (or use an API key, here i used api to communicate).
- Prepare a large file (e.g., 10GB) .
truncate -s 10G large_file.bin
- Send a multipart request to an API function that accepts a file, such as
check_online_status_container:
curl -X POST "http://localhost:8000/api/rpc" \
-H "X-API-Key: YOUR_API_KEY" \
-F "func=check_online_status_container" \
-F "container=@large_file.bin"
- Monitor the server's memory usage. The process will attempt to allocate memory for the entire file and last the process will be killed by the kernel. <img width="1902" height="610" alt="dos-process-kill-poc" src="https://github.com/user-attachments/assets/2b9bfd0f-5b9f-48dd-983f-f97dfcc358cc" />
Impact
- Denial of Service (DoS): The pyLoad process will be killed by the Operating System's Out-Of-Memory (OOM) killer, or the entire system may become unresponsive due to swap thrashing or memory exhaustion.
- Service Instability: Any active downloads or tasks will be interrupted.
Mitigations
- Implement File Size Limits: Enforce a maximum size for uploaded files in the web server configuration (e.g., Nginx
client_max_body_size).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyload-ng | all versions | 0.5.0b3.dev101pip install --upgrade 'pyload-ng==0.5.0b3.dev101' |
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 0.5.0b3.dev101 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-48484 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2026-48484 in your dependencies?
Find it across PyPI, including transitive dependencies.