CVE-2025-57751
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 · uneditedpyLoad is the free and open-source Download Manager written in pure Python. The jk parameter is received in pyLoad CNL Blueprint. Due to the lack of jk parameter verification, the jk parameter input by the user is directly determined as dykpy.evaljs(), resulting in the server CPU being fully occupied and the web-ui becoming unresponsive. This vulnerability is fixed in 0.5.0b3.dev92.
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 confidenceThe jk parameter in pyLoad's CNL Blueprint is passed directly to dykpy.evaljs() without any validation or sanitization. Attackers can submit specially crafted jk parameter values that cause evaljs() to execute expensive JavaScript operations, exhausting server CPU resources and making the web-ui unresponsive.
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
- Authentication
- X
- User interaction
- None
- Scope
- X
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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 checksWork through these to decide whether this CVE applies to you.
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Verify pyLoad installation existsLocate the pyLoad installation directory or check for the 'pyload' package via package manager (e.g., pip show pyload, dpkg -l | grep pyload, or ls /path/to/pyload)Affected if pyLoad is not found on the system - not applicable
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Determine installed pyLoad versionRun 'pyload --version' or check the version file in the pyLoad installation (often in __init__.py or a VERSION file), or use pip show pyloadAffected if Version is less than 0.5.0b3.dev92 (e.g., 0.5.0b3.dev91, 0.5.0b2, etc.) - vulnerable
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Confirm CNL Blueprint is accessibleCheck if the CNL (Click'N'Load) route exists in the pyLoad web interface routes - typically accessible at /cnl or /flash/add and handled by the cnl blueprint moduleAffected if CNL endpoint is exposed and the jk parameter can be submitted without validation - vulnerable if version is below the fixed release
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Verify evaljs usage in CNL handlerInspect the CNL blueprint source code (cnl.py or similar) to confirm the jk parameter is passed to dykpy.evaljs() without sanitization - look for evaljs() calls with jk parameterAffected if The code directly passes request parameters to evaljs() without validation - vulnerable
The environment is affected if pyLoad version is below 0.5.0b3.dev92 AND the CNL Blueprint with the vulnerable jk parameter handling is exposed.
Generated from the published advisory. Verify against your own configuration.
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 · scopedUpgrade pyLoad to version 0.5.0b3.dev92 or later, which implements proper jk parameter validation before passing to evaljs().
0.5.0b3.dev92
- Identify the current pyLoad version running in your environment
- Upgrade pyLoad to version 0.5.0b3.dev92 or later where the jk parameter validation is implemented
- Restart the pyLoad service to apply the update
- Verify the service is running and the web-ui is responsive
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-57751 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-57751 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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