Deserialization of Untrusted DataWeakness · CWE-502

CVE-2025-71359

HIGH · 8.1 CVSS v3.1 Published 2026-07-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
88/100
Remediation priority · High
Remotely reachable No privileges 7 weeks old

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
picklescan before 0.0.29 fails to detect malicious pickle payloads that utilize lib2to3.pgen2.grammar.Grammar.loads in the reduce method, allowing remote code execution. Attackers can craft pickle files embedding dangerous code that evades picklescan detection and executes during pickle.load() deserialization.

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

picklescan before version 0.0.29 fails to detect malicious pickle payloads that abuse lib2to3.pgen2.grammar.Grammar.loads within the __reduce__ method, enabling attackers to craft evasive pickle files that bypass scanner detection and achieve remote code execution upon pickle.load() deserialization.

MitigationUpgrade picklescan to version 0.0.29 or later to include detection for Grammar.loads-based payloads; avoid loading untrusted pickle files regardless of scanner results.

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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. Verify picklescan is installed
    Run 'pip show picklescan' or check your dependency list for the picklescan package
    Affected if picklescan is not installed in your environment - you are not affected as a scanner user, but also not protected
  2. Check the installed version of picklescan
    Run 'pip show picklescan' and look for the Version field, or run 'pip index versions picklescan' to see available versions
    Affected if The installed version is lower than 0.0.29 (e.g., 0.0.28, 0.0.27, etc.) - you are running a vulnerable version
  3. Identify pickle files scanned from untrusted sources
    Review your picklescan usage logs or scripts that invoke picklescan on pickle files from external/untrusted sources
    Affected if You scan pickle files from untrusted or user-controlled sources - these could contain Grammar.loads evasion payloads that your version of picklescan would miss
  4. Test for Grammar.loads detection capability
    Create a test pickle file using lib2to3.pgen2.grammar.Grammar.loads within __reduce__ and scan it with your installed picklescan version to see if it gets flagged
    Affected if Your picklescan version does not detect this specific evasion technique - the malicious payload would be allowed through undetected

You are affected if you have picklescan installed with a version below 0.0.29 AND you use it to scan pickle files from untrusted sources that could contain the Grammar.loads evasion technique.

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 picklescan to version 0.0.29 or later to include detection for Grammar.loads-based payloads; avoid loading untrusted pickle files regardless of scanner results.

Recommended fix High confidence

0.0.29

  1. Upgrade picklescan to version 0.0.29 or later using your package manager (e.g., pip install picklescan==0.0.29)

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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Scan for this in your stack

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dbcve dependency scanner

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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-2025-71359 in production — separate from our analysis above.

No notes yet

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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