CVE-2021-39153
CVSS v3
8.5
HIGH
EPSS Score
4.5 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream, if using the version out of the box with Java runtime version 14 to 8 or with JavaFX installed. 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.
Technical details
- Published
- 2021-08-23
Frequently asked questions
What is CVE-2021-39153?
XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream, if using the version out of the box with Java runtime version 14 to 8 or with JavaFX installed. 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.
Is CVE-2021-39153 actively exploited?
Active exploitation of CVE-2021-39153 has not been confirmed. Its EPSS score was 4.5% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-39153?
CVE-2021-39153 has a CVSS v3 base score of 8.5 (HIGH severity).
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