CVE-2020-26217
Remote Code Execution in XStream
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
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.
Official description from the CVE record, published by GitHub_M. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 3.1 High 8.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
Attack vector: Network
The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity: High
The attack depends on conditions outside the attacker's control, so it takes preparation.
Privileges required: Low
A basic user account is needed.
User interaction: Required
A user has to do something first, such as opening a file or following a link.
Scope: Changed
The impact can reach other components beyond the vulnerable one.
Confidentiality impact: High
Serious or total effect on the secrecy of data.
Integrity impact: High
Serious or total effect on the trustworthiness of data.
Availability impact: High
Serious or total effect on availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity | High | The attack depends on conditions outside the attacker's control, so it takes preparation. |
| Privileges required | Low | A basic user account is needed. |
| User interaction | Required | A user has to do something first, such as opening a file or following a link. |
| Scope | Changed | The impact can reach other components beyond the vulnerable one. |
| Confidentiality impact | High | Serious or total effect on the secrecy of data. |
| Integrity impact | High | Serious or total effect on the trustworthiness of data. |
| Availability impact | High | Serious or total effect on availability. |
CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at first.org/cvss.
EPSS
- Score
- 0.84968 (85.0% probability)
- Percentile
- 99.7%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
CISA assessment as of Oct 7, 2026
- Automatable
- yes
- Technical impact
- total
Weakness (CWE)
- CWE-78Improper Neutralization of Special Elements used in an OS Command
Affected products
x-stream xstream
- affected: < 1.4.14
References
- github.com/x-stream/xstream/security/advisories/GHSA-mw36-7…
- x-stream.github.io/CVE-2020-26217.html
- github.com/x-stream/xstream/commit/0fec095d534126931c99fd38…
- [debian-lts-announce] 20201201 [SECURITY] [DLA 2471-1] libxstream-java security update (lists.debian.org)mailing-list
- DSA-4811 (debian.org)vendor-advisory
- [activemq-issues] 20201230 [jira] [Created] (AMQ-8107) Does ActiveMQ use the affected functionality within Xstream libraries for CVE-2020-26217 (lists.apache.org)mailing-list
- [activemq-issues] 20201230 [jira] [Updated] (AMQ-8107) Does ActiveMQ use the affected functionality within Xstream libraries for CVE-2020-26217 (lists.apache.org)mailing-list
- [activemq-issues] 20210104 [jira] [Resolved] (AMQ-8107) Does ActiveMQ use the affected functionality within Xstream libraries for CVE-2020-26217 (lists.apache.org)mailing-list
- oracle.com/security-alerts/cpuApr2021.html
- security.netapp.com/advisory/ntap-20210409-0004
- oracle.com//security-alerts/cpujul2021.html
- [camel-commits] 20211006 [camel] branch main updated: Camel-XStream: Added a test about CVE-2020-26217 (lists.apache.org)mailing-list
- oracle.com/security-alerts/cpuoct2021.html
- oracle.com/security-alerts/cpujan2022.html
- oracle.com/security-alerts/cpuapr2022.html
Timeline
- ID reserved
- Record published
- Record last updated
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Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:53 UTC. Sources and licenses