CVE-2021-39144
XStream contains a remote code execution vulnerability that allows an attacker to manipulate the processed input stream and replace or inject objects that result in the execution of a local command on the server. This vulnerability can affect multiple products, including but not limited to VMware Cloud Foundation.
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.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H- packetstormsecurity.com/files/169859/VMware-NSX-Manager-XStream-Unauthenticated-Remote-Code-Execution.htmlExploitThird Party Advisory
- github.com/x-stream/xstream/security/advisories/GHSA-j9h8-phrw-h4fhVendor Advisory
- lists.debian.org/debian-lts-announce/2021/09/msg00017.htmlMailing ListThird Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/Broken LinkMailing List
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/Broken LinkMailing List
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/Broken LinkMailing List
- security.netapp.com/advisory/ntap-20210923-0003/Third Party Advisory
- debian.org/security/2021/dsa-5004Third Party Advisory
- oracle.com/security-alerts/cpuapr2022.htmlPatchThird Party Advisory
- oracle.com/security-alerts/cpujan2022.htmlPatchThird Party Advisory
- oracle.com/security-alerts/cpujul2022.htmlPatchThird Party Advisory
- x-stream.github.io/CVE-2021-39144.htmlExploitVendor Advisory
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1306 days
- CVSS
- 8.5 HIGH
- EPSS (30-day exploit probability)
- 98.1% · top 1% of all CVEs
- Weakness
- CWE-94
- Attack vector
- Network, remotely reachable
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.