CVE-2021-39144
XStream — XStream Remote Code Execution Vulnerability
XStream · CWE-94 — Code injection | CWE-502 — Deserialization of untrusted data | CWE-306 · in CISA KEV since 2023-03-10
EVRS 85 of 100 Immediate
Patch Immediately
Rank 371 of 2,960 tracked
Why it scores 85
Evidence available: 6 of 7 signalsListed in the CISA KEV catalog, and an EPSS probability of 0.981.
- CISA KEVApplied
- RansomwareDid not apply
- Vendor exploitationDid not apply
- EPSSApplied
- Microsoft Exploitability IndexNot applicable
- Pre-patch disclosureNo data
- KEV recencyDid not apply
- CVSSApplied
The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data
Fix
Patch or fixed version identifiedCISA required action
Fixed in
- com.thoughtworks.xstream:xstream
1.4.18
Affected versions
- com.thoughtworks.xstream:xstream (maven)
affected < 1.4.18, fixed in 1.4.18
+7 more affected products; see the full list at NVD.
Remediation
Apply updates per vendor instructions.
Fixed versions from NVD and GitHub. Affected packages also in GitHub Advisory GHSA-j9h8-phrw-h4fh (CC BY 4.0).
Evidence
Each value with its source| Measure | Value | Source |
|---|---|---|
| CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. | 8.5 | NVD |
| FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. | 0.981 (99.91st pctl) | FIRST EPSS |
| Actively exploitedWhether a source of record has confirmed attacks using it in the wild. | Confirmed | CISA KEV |
| Ransomware campaign useWhether CISA has seen ransomware operators use it. | Unknown or none | CISA KEV |
| CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. | 2023-03-31 · KEV since 2023 · listed over a year | CISA KEV |
| Public exploit moduleA module existing is not the same as active exploitation. | Public module exists | Metasploit |
| EUVD cross-referenceENISA's record: CVSS 8.5 (v3.1), assigned by GitHub_M. | Listed | ENISA EUVD |
Description
NVDXStream 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.
What CISA says to do
Public module
Metasploit lists a public excellent-rank module for this CVE: VMware NSX Manager XStream unauthenticated RCE (linux/http/vmware_nsxmgr_xstream_rce_cve_2021_39144). A module existing is not the same as active exploitation; see metasploit.com.