Summary
Spring Security does not consider URL path parameters when processing security constraints. By adding a URL path parameter with an encoded "/" to a request, an attacker may be able to bypass a security constraint. The root cause of this issue is a lack of clarity regarding the handling of path parameters in the Servlet Specification (see below). Some Servlet containers include path parameters in the value returned for getPathInfo() and some do not. Spring Security uses the value returned by getPathInfo() as part of the process of mapping requests to security constraints. The unexpected presence of path parameters can cause a constraint to be bypassed.
Users of Apache Tomcat (all current versions) are not affected by this vulnerability since Tomcat follows the guidance previously provided by the Servlet Expert group and strips path parameters from the value returned by getContextPath(), getServletPath() and getPathInfo() [1].
Users of other Servlet containers based on Apache Tomcat may or may not be affected depending on whether or not the handling of path parameters has been modified.
Users of IBM WebSphere Application Server 8.5.x are known to be affected.
Users of other containers that implement the Servlet specification may be affected.
[1] https://issues.apache.org/bugzilla/show_bug.cgi?id=25015
Affected Pivotal Products and Versions
Severity is high unless otherwise noted.
- Spring Security 3.2.0 - 3.2.9
- Spring Security 4.0.x - 4.1.3
- Spring Security 4.2.0
- Older unsupported versions are also affected
Mitigation
Adopting one of the following mitigations will protect against this vulnerability.
- Use a Servlet container known not to include path parameters in the return values for getServletPath() and getPathInfo()
- Upgrading to Spring Security 3.2.10, 4.1.4 or 4.2.1 will reject the request with a RequestRejectedException if the presence of an encoded "/" is detected. Note: If you wish to disable this feature it can be disabled by setting the DefaultHttpFirewall.allowUrlEncodedSlash = true. However, disabling this feature will mean applications are vulnerable (in containers that return path parameters in getServletPath() or getPathInfo()).
Credit
The issue was identified by Shumpei Asahara & Yuji Ito from NTT DATA Corporation and responsibly reported to Pivotal.
Impact
CVE-2016-9879 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.2.10.RELEASE, 4.1.4.RELEASE, 4.2.1.RELEASE); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
org.springframework.security:spring-security-core to 3.2.10.RELEASE or later; org.springframework.security:spring-security-core to 4.1.4.RELEASE or later; org.springframework.security:spring-security-core to 4.2.1.RELEASE or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2016-9879? CVE-2016-9879 is a high-severity security vulnerability in org.springframework.security:spring-security-core (maven), affecting versions < 3.2.10.RELEASE. It is fixed in 3.2.10.RELEASE, 4.1.4.RELEASE, 4.2.1.RELEASE.
- How severe is CVE-2016-9879? CVE-2016-9879 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.springframework.security:spring-security-core are affected by CVE-2016-9879? org.springframework.security:spring-security-core (maven) versions < 3.2.10.RELEASE is affected.
- Is there a fix for CVE-2016-9879? Yes. CVE-2016-9879 is fixed in 3.2.10.RELEASE, 4.1.4.RELEASE, 4.2.1.RELEASE. Upgrade to this version or later.
- Is CVE-2016-9879 exploitable, and should I be worried? Whether CVE-2016-9879 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2016-9879 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2016-9879?
- Upgrade
org.springframework.security:spring-security-coreto 3.2.10.RELEASE or later - Upgrade
org.springframework.security:spring-security-coreto 4.1.4.RELEASE or later - Upgrade
org.springframework.security:spring-security-coreto 4.2.1.RELEASE or later
- Upgrade