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CVE-2020-26258

HIGHCVSS 7.7/10EPSS 81.44%

Last modified

CVE-2020-26258 is a high-severity vulnerability rated 7.7/10 on the CVSS scale. 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. EPSS estimates a 81.44% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
7.7/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS Probability
81.44%

99.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
ApacheStruts< 6.0.0
XstreamXstream< 1.4.15
DebianDebian Linux9.0
DebianDebian Linux10.0
FedoraprojectFedora33
FedoraprojectFedora34
FedoraprojectFedora35

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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.
How severe is CVE-2020-26258?
CVE-2020-26258 has a CVSS score of 7.7/10 (HIGH severity). The EPSS model estimates a 81.44% probability of exploitation in the next 30 days.
How do I fix CVE-2020-26258?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26258?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST