xstreamproject xstream CVE-2020-26258 vulnerability in Xstreamproject and Other Products
Published on December 16, 2020

Server-Side Forgery Request can be activated unmarshalling with XStream

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XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.15, a Server-Side Forgery Request vulnerability can be activated when unmarshalling. The vulnerability may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.15. The reported vulnerability does not exist if running Java 15 or higher. No user is affected who followed the recommendation to setup XStream's Security Framework with a whitelist! Anyone relying on XStream's default blacklist can immediately switch to a whilelist for the allowed types to avoid the vulnerability. Users of XStream 1.4.14 or below who still want to use XStream default blacklist can use a workaround described in more detailed in the referenced advisories.

Github Repository NVD

Vulnerability Analysis

CVE-2020-26258 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
NONE
Availability Impact:
NONE

Weakness Type

What is a SSRF Vulnerability?

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.

CVE-2020-26258 has been classified to as a SSRF vulnerability or weakness.


Products Associated with CVE-2020-26258

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2020-26258 are published in these products:

Xstreamproject Xstream
 
Debian Linux
 
Canonical Ubuntu Linux
 
Fedora Project Fedora
 
Apache Struts
 
Xstream
 

Affected Versions

x-stream xstream Version < 1.4.15 is affected by CVE-2020-26258

Vulnerable Packages

The following package name and versions may be associated with CVE-2020-26258

Package Manager Vulnerable Package Versions Fixed In
maven com.thoughtworks.xstream:xstream < 1.4.15 1.4.15

Exploit Probability

EPSS
93.68%
Percentile
99.84%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.