CVE-2026-40594

Description

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev98, the set_session_cookie_secure before_request handler in src/pyload/webui/app/__init__.py reads the X-Forwarded-Proto header from any HTTP request without validating that the request originates from a trusted proxy, then mutates the global Flask configuration SESSION_COOKIE_SECURE on every request. Because pyLoad uses the multi-threaded Cheroot WSGI server (request_queue_size=512), this creates a race condition where an attacker's request can influence the Secure flag on other users' session cookies — either downgrading cookie security behind a TLS proxy or causing a session denial-of-service on plain HTTP deployments. This vulnerability is fixed in 0.5.0b3.dev98.

CVSS v3.1 Score

4.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-346 CWE-346

Affected Products

Vendor	Product	Versions
pyload-ng_project	pyload-ng	< 0.5.0b3.dev69

References

Advisories & Patches

https://github.com/pyload/pyload/security/advisories/GHSA-mp82-fmj6-f22v https://github.com/pyload/pyload/security/advisories/GHSA-mp82-fmj6-f22v

Exploits

https://github.com/pyload/pyload/security/advisories/GHSA-mp82-fmj6-f22v https://github.com/pyload/pyload/security/advisories/GHSA-mp82-fmj6-f22v

Frequently Asked Questions

What is CVE-2026-40594? +

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev98, the set_session_cookie_secure before_request handler in src/pyload/webui/app/__init__.py reads the X-Forwarded-Proto header from any HTTP request without validating that the request originates from a trusted proxy, then mutates the global Flask configuration SESSION_COOKIE_SECURE on every request. Because pyLoad uses the multi-threaded Cheroot WSGI server (request_queue_size=512), this creates a race condition where an attacker's request can influence the Secure flag on other users' session cookies — either downgrading cookie security behind a TLS proxy or causing a session denial-of-service on plain HTTP deployments. This vulnerability is fixed in 0.5.0b3.dev98. It has a CVSS v3.1 base score of 4.8 (MEDIUM).

How severe is CVE-2026-40594? +

CVE-2026-40594 has a CVSS v3.1 score of 4.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-40594? +

CVE-2026-40594 affects products from pyload-ng_project, specifically: pyload-ng. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-40594? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-22077

OPPO Wallet APP contains a trusted domain validation flaw that allows attackers to bypass protected interface access restrictions, which may …

CVE-2026-44985

Dozzle is a realtime log viewer for docker containers. Prior to 10.5.2, he WebSocket upgrader for the /exec and /attach …

CVE-2025-3651

Improper Verification of Source of a Communication Channel in Work Desktop for Mac versions 10.8.1.46 and earlier allows attackers to …

CVE-2025-3462

"This issue is limited to motherboards and does not affect laptops, desktop computers, or other endpoints." An insufficient validation in …

CVE-2025-53399

In Sipwise rtpengine before 13.4.1.1, an origin-validation error in the endpoint-learning logic of the media-relay core allows remote attackers to …

CVE-2025-10193

DNS rebinding vulnerability in Neo4j Cypher MCP server allows malicious websites to bypass Same-Origin Policy protections and execute unauthorised tool …