If left unpatched, CVE-2020-26258 could lead to major system disruptions or data loss.
Status: Modified
Last updated: 🕘 15 Jan 2025, 21:15 UTC
Originally published on: 🕐 16 Dec 2020, 01:15 UTC
Time between publication and last update: 1491 days
CVSS Release: version 3
security-advisories@github.com
Secondary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
CVE-2020-26258: 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.
The exploitability of CVE-2020-26258 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
This vulnerability, CVE-2020-26258, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2020-26258, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2020-26258, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 85.133% (probability of exploit)
EPSS Percentile: 98.82%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 1.1800000000000068% of others.
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