Description

This CVE addresses a second path to exploiting the same vulnerability as the one described under CVE-2017-4971.

Applications that do not change the value of the MvcViewFactoryCreator useSpringBinding property which is disabled by default (i.e. set to “false”) can be vulnerable to malicious EL expressions in view states that process form submissions but do not have a sub-element to declare explicit data binding property mappings.

Affected Spring Products and Versions

• Spring Web Flow 2.4.0 to 2.4.5
• Older unsupported versions are also affected

Mitigation

Users of affected versions should apply the following mitigation:

• 2.4.x users should upgrade to 2.4.6

Note that generally it is a good practice and recommended to always use explicit data binding declarations in view states in order to prevent form submissions from setting fields on the target object that should not be set.

Users of Spring Web Flow with JSF are not impacted by this report.

Credit

The issue was identified by security researcher he1renyagao.

References

• Issue tracker ticket https://jira.spring.io/browse/SWF-1711'>SWF-1711</a>;.
• Commits https://github.com/spring-projects/spring-webflow/commit/df0eab'>df0eab</a> and https://github.com/spring-projects/spring-webflow/commit/ed5e8c'>ed5e8c</a> on master branch (2.4.6 release).
• Commits https://github.com/spring-projects/spring-webflow/commit/084b4e'>084b4e</a> on 2.5.x branch (2.5.RC1 release).

History

2017-09-15: Initial vulnerability report published