CVE-2021-39144
XStream is vulnerable to a Remote Command Execution attack
- High 8.5
- Exploited: added to CISA KEV 10 Mar 2023
Description
XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.
Key facts
- Published
- 23 Aug 2021
- Last changed
- 21 Oct 2025
- Assigned by
- GitHub_M
- KEV added
- 10 Mar 2023
- KEV fix due
- 31 Mar 2023
- EPSS
- 98.124% likely to be exploited in the next 30 days, higher than 99.913% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: no; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 8.5CVSS 3.1, Highfrom the CNA (GitHub_M)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
What to do
- Apply updates per vendor instructions.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| x-stream | xstream |
|
Timeline
- 23 Aug 2021 Published
- 10 Mar 2023 CVE-2021-39144 added to CISA KEV
- 10 Mar 2023 Added to the CISA KEV catalogue