dbcve.org
Code InjectionWeakness · CWE-94

CVE-2025-53890

CRITICAL · 9.8 CVSS v3.1 Published 2025-07-15
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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 an open-source Download Manager written in pure Python. An unsafe JavaScript evaluation vulnerability in pyLoad’s CAPTCHA processing code allows unauthenticated remote attackers to execute arbitrary code in the client browser and potentially the backend server. Exploitation requires no user interaction or authentication and can result in session hijacking, credential theft, and full system remote code execution. Commit 909e5c97885237530d1264cfceb5555870eb9546, the patch for the issue, is included in version 0.5.0b3.dev89.

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 contains an unsafe JavaScript evaluation vulnerability in its CAPTCHA processing component. Unauthenticated remote attackers can exploit this flaw to execute arbitrary code in the client browser, potentially leading to session hijacking, credential theft, and full system remote code execution on the backend server.

MitigationUpgrade pyLoad to version 0.5.0b3.dev89 or later to incorporate the patched code from commit 909e5c97885237530d1264cfceb5555870eb9546.

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Verify pyLoad installation
    Check if pyLoad is installed on the system by looking for the pyLoad application directory, service, or by running 'pip show pyload' or checking common installation paths like /opt/pyload, /usr/local/pyload, or the application's home directory.
    Affected if pyLoad is installed and running
  2. Determine installed pyLoad version
    Run 'pyload --version' or check the version file in the pyLoad installation directory, commonly found in setup.py, __init__.py, or a VERSION file within the pyload package.
    Affected if The installed version is earlier than 0.5.0b3.dev89 (the fixed release)
  3. Check if CAPTCHA module is enabled
    Inspect pyLoad configuration files (typically pyload.conf or settings.json) for CAPTCHA-related settings, or check if the CAPTCHA processing functionality is loaded in the running application.
    Affected if CAPTCHA processing is enabled and the installed version is before 0.5.0b3.dev89
  4. Inspect CAPTCHA code for unsafe JavaScript evaluation (optional advanced check)
    Examine the CAPTCHA processing source code files in the pyLoad installation, looking for eval() or similar JavaScript execution functions being used on user-supplied CAPTCHA responses.
    Affected if The code contains unsafe JavaScript evaluation on CAPTCHA input and the version is before 0.5.0b3.dev89

A user is affected if pyLoad is running with a version earlier than 0.5.0b3.dev89 and has CAPTCHA functionality enabled, as the unsafe JavaScript evaluation in the CAPTCHA processing code can be exploited.

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
Patch available Apply the vendor patch
Vendor patch github.com →
Interim mitigation

Upgrade pyLoad to version 0.5.0b3.dev89 or later to incorporate the patched code from commit 909e5c97885237530d1264cfceb5555870eb9546.

Recommended fix Moderate confidence

version 0.5.0b3.dev89

  1. Backup your current pyload installation and configuration before proceeding with the upgrade
  2. Upgrade pyload to version 0.5.0b3.dev89 or later where the patch (commit 909e5c97885237530d1264cfceb5555870eb9546) is included
  3. After upgrading, verify that the CAPTCHA processing functionality works correctly and that the unsafe JavaScript evaluation has been remediated
  4. Review application logs to ensure no exploitation attempts occurred prior to the upgrade
Caveat beta/dev versions may have other changes; test in a non-production environment first

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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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-2025-53890 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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data