CVE-2025-50461
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 · uneditedA deserialization vulnerability exists in Volcengine's verl 3.0.0, specifically in the scripts/model_merger.py script when using the "fsdp" backend. The script calls torch.load() with weights_only=False on user-supplied .pt files, allowing attackers to execute arbitrary code if a maliciously crafted model file is loaded. An attacker can exploit this by convincing a victim to download and place a malicious model file in a local directory with a specific filename pattern. This vulnerability may lead to arbitrary code execution with the privileges of the user running the script.
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 confidenceIn Volcengine verl 3.0.0, the scripts/model_merger.py script uses torch.load() with weights_only=False when loading .pt model files in the 'fsdp' backend. This unsafe deserialization allows arbitrary code execution if a victim downloads and places a specially crafted malicious model file with a specific filename pattern in a local directory.
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
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify if Volcengine verl is installedRun 'pip show volcengine-verl' or check for the verl package in your Python environmentAffected if volcengine-verl version 3.0.0 is installed
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Locate the model_merger.py scriptFind scripts/model_merger.py in the verl installation directory, typically in the volcengine-verl package pathAffected if The script exists in the installed package
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Verify unsafe torch.load() usageOpen model_merger.py and search for torch.load() calls, check if weights_only parameter is set to False or not setAffected if torch.load() is called with weights_only=False or without specifying weights_only when using the fsdp backend
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Check for fsdp backend configurationIn model_merger.py, locate the code path that handles the 'fsdp' backend and confirms it calls the unsafe torch.load()Affected if The fsdp backend code path loads .pt files using the unsafe torch.load()
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Inspect for untrusted .pt model filesSearch local directories for .pt model files, particularly any with unusual origin or that match patterns the script expects (check the filename patterns in model_merger.py)Affected if Untrusted or externally sourced .pt model files exist in directories accessible to the script
You are affected if you run Volcengine verl 3.0.0, use the fsdp backend in model_merger.py to load .pt files, and have untrusted or malicious model files present in your environment.
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.
From vendor dataChange torch.load() calls to use weights_only=True, or implement cryptographic signature validation of model files before loading to prevent deserialization of untrusted pickled data.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-50461 — 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-2025-50461 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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- Version or environment caveats, and links to real fixes
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