CVE-2026-3490
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 1.0.4 fails to block pkgutil.resolve_name, allowing attackers to bypass the entire blocklist by resolving any dangerous function through indirect REDUCE calls. Remote attackers can invoke any blocked function such as os.system, builtins.exec, or subprocess.call to achieve 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 · moderate confidencepicklescan before 1.0.4 fails to block pkgutil.resolve_name, allowing attackers to bypass the entire blocklist by resolving dangerous functions (os.system, builtins.exec, subprocess.call) through indirect REDUCE calls, achieving 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
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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' to see if the package is present in your Python environmentAffected if picklescan is installed and being used to scan untrusted pickle files
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Determine the installed versionRun 'pip show picklescan' and look for the Version field, or 'pip freeze | grep picklescan'Affected if The version is below 1.0.4 (e.g., 1.0.3, 1.0.2, etc.)
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Verify the scanning mechanism in useInspect the code that invokes picklescan - look for Scanner, scan_file, scan_bytes, or similar functions being called on untrusted pickle inputAffected if picklescan is actively being used to scan pickle files from untrusted sources
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Confirm blocklist mode is in effectReview picklescan usage in your codebase - the vulnerable versions use a blocklist approach by default to block dangerous operationsAffected if picklescan is scanning pickles using its blocklist-based filtering (the default behavior in versions before 1.0.4)
You are affected if picklescan version below 1.0.4 is installed and being used to scan untrusted pickle files using its blocklist-based scanning capability.
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 to picklescan 1.0.4 or later which includes pkgutil.resolve_name in the blocklist; implement defense-in-depth with input validation, sandboxing, and avoid relying solely on pickle scanning for security.
picklescan 1.0.4 or later
- Identify the current version of picklescan in your project by checking your dependency files (requirements.txt, setup.py, pyproject.toml, or Pipfile)
- Upgrade picklescan to version 1.0.4 or later using your package manager: pip install picklescan>=1.0.4 or pip install --upgrade picklescan
- Verify the upgrade was successful by running: pip show picklescan and confirming the version number
- Re-scan your Python pickle files with the updated picklescan to ensure the blocklist now properly mitigates the pkgutil.resolve_name bypass vector
- Update your lock files (e.g., requirements-lock.txt) to pin the fixed version for reproducible builds
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-3490 — 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-2026-3490 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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