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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-45348

HIGH · 8.7 CVSS v3.1 Published 2026-05-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
91/100
Remediation priority · Urgent
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev100, 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. This vulnerability is fixed in 0.5.0b3.dev100.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

pyLoad versions prior to 0.5.0b3.dev100 contain a stored Cross-Site Scripting (XSS) vulnerability in the packages.js template. The application directly interpolates a stored link URL into a single-quoted HTML attribute within a template literal, then writes the result to the DOM using $(div).html(html) without any sanitization or escaping. An attacker who can submit package links can inject a single quote followed by an event handler to break out of the attribute and execute arbitrary JavaScript in any operator's browser.

MitigationUpgrade pyLoad to version 0.5.0b3.dev100 or later, which implements proper escaping. Additionally, configure a Content Security Policy (CSP) that restricts inline scripts and event handlers to provide defense-in-depth against XSS attacks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify pyLoad version
    Locate the pyLoad installation and check its version file, or access the web interface and look for version information in the footer or admin panel. Common locations include a version.py file or the application's about/settings page.
    Affected if The installed version is earlier than 0.5.0b3.dev100 (e.g., 0.5.0b3.dev99, 0.4.x, or earlier releases).
  2. Verify packages.js template exists
    Inspect the pyLoad web application files for the presence of packages.js or a similar template file that handles package link display. This is typically found in the templates or static assets directory of the web interface.
    Affected if The template file exists and contains JavaScript code that uses $(div).html() or similar methods to render user-supplied link URLs into the DOM.
  3. Confirm web interface is enabled
    Check the pyLoad configuration (typically pyload.conf or settings) to determine whether the web interface/API is active and accessible to operators.
    Affected if The web interface is enabled and operators can access the package management features where submitted links are displayed.
  4. Check if link submission feature is accessible
    Determine whether any user role (including non-admin operators) can add or submit package links through the web interface or API.
    Affected if Operators or any users with access can submit package links that get stored and rendered through the vulnerable template.

You are affected if pyLoad version is prior to 0.5.0b3.dev100 AND the web interface with package link display is enabled and accessible to users who can submit links.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade pyLoad to version 0.5.0b3.dev100 or later, which implements proper escaping. Additionally, configure a Content Security Policy (CSP) that restricts inline scripts and event handlers to provide defense-in-depth against XSS attacks.

Recommended fix High confidence

0.5.0b3.dev100

  1. 1. Identify the current pyLoad version by checking the installed package or source code.
  2. 2. Upgrade pyLoad to version 0.5.0b3.dev100 or later. This can typically be done via pip (pip install --upgrade pyload), or by pulling the latest Docker image if using containerized deployment.
  3. 3. After upgrading, verify the fix by checking that src/pyload/webui/app/themes/modern/templates/js/packages.js no longer interpolates raw URL values into HTML template literals without escaping.
  4. 4. For operators who cannot upgrade immediately, a temporary mitigation is to configure a Content Security Policy (CSP) header in the web server or reverse proxy to restrict inline scripts and event handlers (e.g., 'script-src 'self'; style-src 'self' 'unsafe-inline'').
  5. 5. Restrict the ability to submit/add package links to trusted users only until the upgrade is completed.

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45348 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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