The vulnerability may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service 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.
See workarounds for the different versions covering all CVEs.
See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for CVE-2021-39140.
The vulnerability was discovered and reported by Lai Han of nsfocus security team.
If you have any questions or comments about this advisory: * Open an issue in XStream * Contact us at XStream Google Group