pyLoad: Lack of Input Size Validation Leads to Denial of Service (DoS) and Process Termination

published 2026-10-09 30 d ago modified 2026-10-15 24 d ago also GHSA-vq8p-m3wm-gv5f , PYSEC-2026-4293 , EUVD-2026-95910

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits: 0; none known

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev101, 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. Version 0.5.0b3.dev101 contains a patch.

Patch / fix

fixed in 1 links 1

pypi pyload-ng 0.5.0b3.dev101

github.com/pyload/pyload@461cd66 commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 26 d ago (2026-10-14)

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/pyload/pyload/security/advisories/GHSA-vq8p-m3wm-gv5f referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
OSV	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
GitHub	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
pypi	pyload-ng	<0.5.0b3.dev101	0.5.0b3.dev101

Affected products

pyload pyload

Classification

Weakness

CWE-20 Improper Input Validation
CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary