Improper Authentication and Origin Validation Error in pyload-ng

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-33314: 0.19% estimated exploitation activity in the next 30 days; percentile 8.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A Host Header Spoofing vulnerability in the @localcheck decorator allows unauthenticated external attackers to bypass local-only restrictions. This grants access to the Click'N'Load API endpoints, enabling attackers to remotely queue arbitrary downloads, leading to Server-Side Request Forgery (SSRF) and Denial of Service (DoS). Details The pyload WebUI provides an API for the Click'N'Load plugin, which is intended to be accessed only from the local machine (e.g., via a browser extension sending requests to localhost:9666). To enforce this, the pyload application uses a @localcheck decorator on the relevant routes in src/pyload/webui/app/blueprints/cnlblueprint.py. However, the @localcheck implementation relies on the user-controlled HTTPHOST (derived from the HTTP Host header) to verify the origin: Because httphost is read directly from the Host header of the HTTP request, an external attacker can easily spoof this header (e.g., Host: 127.0.0.1:9666). When this spoofed header…

Published by the source

19 Mar 2026, 17:55 UTC

Last modified by the source

8 Jun 2026, 19:15 UTC

Source last checked

26 Oct 2026, 13:44 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-q485-cg9q-xq2r

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-q485-cg9q-xq2r

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# Patch Next advisory brief: CVE-2026-33314

Advisory: Improper Authentication and Origin Validation Error in pyload-ng
IDs: CVE-2026-33314, GHSA-q485-cg9q-xq2r
Record: https://patchnext.com/advisories/cve-2026-33314 (revision 2, source checked 26 Oct 2026, 13:44 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pyload-ng 0.5.0b3.dev97. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pyload-ng: affected <= 0.5.0b3.dev96; fixed in 0.5.0b3.dev97

## Suggested inspection (read-only)
- `python -m pip show pyload-ng`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pyload-ng.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-q485-cg9q-xq2r (OSV record GHSA-q485-cg9q-xq2r lists affected ranges: PyPI pyload-ng >=0 <0.5.0b3.dev97 (fixed))
- Verified: https://github.com/advisories/GHSA-q485-cg9q-xq2r (GitHub-reviewed advisory GHSA-q485-cg9q-xq2r lists affected ranges: PyPI pyload-ng >=0 <=0.5.0b3.dev96)

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