CVE-2025-71321
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 · uneditedpicklescan before 0.0.33 contains an arbitrary file writing vulnerability that allows attackers to bypass the dangerous blocklist by using distutils.file_util.write_file. Attackers can construct malicious pickle objects to overwrite critical system files and achieve denial of service or remote code execution.
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 confidencepicklescan before 0.0.33 has an arbitrary file write vulnerability where attackers bypass the dangerous function blocklist by using distutils.file_util.write_file instead of directly blocked pickle operations. This allows writing malicious content to arbitrary filesystem locations, enabling system file overwrites for denial of service or remote code execution.
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 checksWork through these to decide whether this CVE applies to you.
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Check if picklescan is installedRun `pip show picklescan` or `pip list | grep picklescan`Affected if picklescan is not installed or not found in the environment
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Determine installed versionRun `pip show picklescan` and look for the Version field, or use `pip list --format=freeze | grep picklescan`Affected if Version is below 0.0.33 (for example, 0.0.32, 0.0.31, etc.)
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Verify the blocklist includes the bypassed functionInspect the picklescan source code in the installed package directory (look for the blocklist or dangerous functions list) and check if `distutils.file_util.write_file` is includedAffected if The blocklist does not include `distutils.file_util.write_file` or the function is absent from the blocklist definition
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Identify if processing untrusted pickle filesReview application code or scanning workflows that use picklescan to determine if it processes pickle files from untrusted or external sourcesAffected if picklescan is used to scan pickle files from untrusted or user-controlled sources
You are affected if picklescan with a version below 0.0.33 is installed and is used to scan untrusted pickle files, and the blocklist does not include distutils.file_util.write_file.
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 picklescan to version 0.0.33 or later which includes the patched blocklist. If upgrading is not immediately feasible, consider restricting pickle file processing to trusted sources only.
0.0.33
- Verify the current version of picklescan installed in your environment using 'pip show picklescan' or your package manager
- Upgrade picklescan to version 0.0.33 or later using 'pip install picklescan>=0.0.33'
- Verify the upgrade was successful by running 'pip show picklescan' and confirming the version number
- If using picklescan in a project, update any pinned version requirements to >=0.0.33
- Test that your workflows using picklescan continue to function correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-71321 — 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-2025-71321 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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