S4E just found a high-severity finding from top 10 tcp port service scan
PlatformPlansPartners
Resources
ToolsBlogDocs
Sign Up →
high·Product Based Web Vulnerabilities·Updated Mar 4, 2024

CVE-2021-39144 Scanner

CVE-2021-39144 scanner - Remote Code Execution vulnerability in XStream

Est. Time~10 seconds
Scan TypeSingle Scan
Targetsdomain, ipv4, subdomain
CostFree
3.5k
Times Used
continuous scan runs
5.1k
Continuously Checked
assets under CS
0
Vulnerabilities Found
confirmed findings
References
🔴
CISA Known Exploited Vulnerability
This CVE is actively exploited in the wild. CISA mandates federal agencies to patch immediately.
CVECVE-2021-39144
8.5
CVSShigh
Exploitable remotely over the internet · low-privilege account sufficient.

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.

Attack Vector
Network
Privileges Req.
Low
User Interaction
None
Affected
xstreamby x-stream
< 1.4.18
Updated Aug 21, 2026View on NVD →
Detail

XStream is a widely used Java library for serializing and deserializing objects. It converts Java objects to XML and back again, enabling applications to easily transmit and store complex data structures. XStream's simplicity and flexibility have made it a popular choice for many developers working on applications that require extensive data manipulation and storage capabilities. However, vulnerabilities within XStream, such as CVE-2021-39144, can pose significant security risks, potentially allowing attackers to execute arbitrary code remotely.

The exploitation of CVE-2021-39144 involves crafting a malicious XML payload that, when processed by XStream, triggers the execution of arbitrary code. This can be achieved by including a specially crafted java.util.PriorityQueue object within the XML, which leverages dynamic proxies to execute malicious code. The impact of this vulnerability is heightened due to XStream's widespread use, potentially affecting a wide range of applications.

The exploitation of this vulnerability could lead to unauthorized access to systems, data leakage, and the execution of arbitrary commands on the server hosting the vulnerable application. Attackers could use this to gain a foothold within the affected system, escalate privileges, and potentially move laterally within the network, compromising additional systems and data.

By utilizing the security scanning services provided by S4E, users can identify and mitigate vulnerabilities such as CVE-2021-39144 in their digital infrastructure. Our platform enables users to conduct comprehensive security assessments, identify vulnerabilities early, and implement effective security measures to protect against potential threats. Joining our platform allows users to enhance their cybersecurity posture and safeguard their critical assets.

 

References

Solution Advice
  1. Immediately upgrade to the latest version of XStream that addresses this vulnerability.
  2. Follow security best practices for using serialization libraries, including implementing allow-lists to restrict classes that can be deserialized.
  3. Regularly review and update third-party libraries to ensure they are not vulnerable to known exploits.
  4. Conduct thorough security assessments of applications to identify and mitigate potential vulnerabilities related to serialization and deserialization.
  5. Educate development teams on secure coding practices to prevent the introduction of vulnerabilities in software projects.

Get AI-powered remediation steps tailored to your asset.

Try AI Solutions →

Check your infrastructure.
Right now.

11,000+ scanners. Free to start. No credit card required.

CVE-2021-39144 scanner - Remote Code Execution vulnerability in XStream | S4E