How severe is CVE-2026-40594?

CVE-2026-40594 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.

Is CVE-2026-40594 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40594?

CVE-2026-40594 affects Pyload-ng Project Pyload-ng. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40594?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40594 have an EU (EUVD) identifier?

Yes. CVE-2026-40594 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24207.

When was CVE-2026-40594 published?

CVE-2026-40594 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-40594

CVE-2026-40594 is a medium-severity vulnerability in Pyload-ng Project Pyload-ng with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-346.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24207
Weakness: CWE-346
Affected product: Pyload-ng Project Pyload-ng
Published: 2026-04-21
Last modified: 2026-06-17

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.

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.
How severe is CVE-2026-40594?: CVE-2026-40594 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.
Is CVE-2026-40594 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40594?: CVE-2026-40594 affects Pyload-ng Project Pyload-ng. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40594?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40594 have an EU (EUVD) identifier?: Yes. CVE-2026-40594 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24207.
When was CVE-2026-40594 published?: CVE-2026-40594 was published on 2026-04-21 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:pyload-ng_project:pyload-ng:*:*:*:*:*:python:*:*

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