CVE-2016-4003 Cross-site Scripting in Apache Struts

What is CVE-2016-4003?

CVE-2016-4003 is a medium-severity cross-site scripting vulnerability in Apache Struts, published on 12 Apr 2016. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Cross-site scripting (XSS) vulnerability in the URLDecoder function in JRE before 1.8, as used in Apache Struts 2.x before 2.3.28, when using a single byte page encoding, allows remote attackers to inject arbitrary web script or HTML via multi-byte characters in a url-encoded parameter.

Weakness: CWE-79

Which versions are affected by CVE-2016-4003?

2 open source packages ship an affected version, including org.apache.struts:struts2-core. It affects 1 product.

Products include Apache Struts.

How do I fix CVE-2016-4003?

Upgrade org.apache.struts:struts2-core to 2.3.28 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2016-4003 being exploited?

There is no known exploitation of CVE-2016-4003 in the wild and no public exploit code.

Other vulnerabilities in Apache Struts

• CVE-2020-17530 Apache Struts Remote Code Execution Exploited Critical 9.8
• CVE-2017-9791 Apache Struts 1 Improper Input Validation Exploited Critical 9.8
• CVE-2017-5638 Apache Struts Remote Code Execution Exploited Critical 9.8
• CVE-2012-0391 Apache Struts 2 Improper Input Validation Exploited Critical 9.8
• CVE-2018-11776 Apache Struts Remote Code Execution Exploited High 8.1

All Apache Struts vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CVE-2016-0759, GHSA-m3x6-9v6h-4g28.