pyLoad is vulnerable to stored XSS in Downloads view via unsanitized link URL in packages.js template literal

Exploitation

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

CVSS

8.7 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-45348: 0.20% estimated exploitation activity in the next 30 days; percentile 9.78 (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 The packages.js template at src/pyload/webui/app/themes/modern/templates/js/packages.js:172 interpolates a stored link URL into a template literal inside single-quoted HTML and then writes the result to the DOM via $(div).html(html). No escaping runs between the API value and innerHTML. An attacker (Alice) who can submit a package link puts a single quote plus event handler into the URL, breaks out of the attribute, and executes JavaScript in every operator's browser that opens the downloads view. The theme does not set a Content Security Policy that restricts inline script or event handlers. Details Sink: src/pyload/webui/app/themes/modern/templates/js/packages.js:165-188: link.url flows in from /api/getpackagedata, which returns the URL exactly as stored. Seven other fields on the same element (link.name, link.statusmsg, link.error, link.formatsize, link.plugin, link.icon, link.id) share the same unescaped injection surface. Source: src/pyload/core/api/init.py:541-600…

Published by the source

14 May 2026, 20:23 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:45 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-fcjq-435v-jx94

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-fcjq-435v-jx94

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# Patch Next advisory brief: CVE-2026-45348

Advisory: pyLoad is vulnerable to stored XSS in Downloads view via unsanitized link URL in packages.js template literal
IDs: CVE-2026-45348, GHSA-fcjq-435v-jx94
Record: https://patchnext.com/advisories/cve-2026-45348 (revision 2, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pyload-ng: affected <= 0.5.0b3.dev99

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

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## 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-fcjq-435v-jx94 (OSV record GHSA-fcjq-435v-jx94 lists affected ranges: PyPI pyload-ng >=0 <=0.5.0b3.dev99)
- Verified: https://github.com/advisories/GHSA-fcjq-435v-jx94 (GitHub-reviewed advisory GHSA-fcjq-435v-jx94 lists affected ranges: PyPI pyload-ng >=0 <=0.5.0b3.dev99)

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