Affected: VMware Spring Framework

Spring MVC and WebFlux applications are vulnerable to cache poisoning when resolving static resources.

More precisely, an application can be vulnerable when all the following are true:

* the application is using Spring MVC or Spring WebFlux * the application is configuring the  resource chain support https://docs.spring.io/spring-framework/reference/web/webmvc/mvc-config/static-resources.html#page-title  with caching enabled * the application adds support for encoded resources resolution * the resource cache must be empty when the attacker has access to the application

When all the conditions above are met, the attacker can send malicious requests and poison the resource cache with resources using the wrong encoding. This can cause a denial of service by breaking the front-end application for clients.

Affected: Maven: org.apache.logging.log4j:log4j-core

Apache Log4j Core's [`XmlLayout`](https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout), in versions up to and including 2.25.3, fails to sanitize characters forbidden by the [XML 1.0 specification](https://www.w3.org/TR/xml/#charsets), producing invalid XML output whenever a log message or MDC value contains such characters.

The impact depends on the StAX implementation in use:

* **JRE built-in StAX**: Forbidden characters are silently written to the output, producing malformed XML. Conforming parsers must reject such documents with a fatal error, which may cause downstream log-processing systems to drop the affected records. * **Alternative StAX implementations** (e.g., [Woodstox](https://github.com/FasterXML/woodstox), a transitive dependency of the Jackson XML Dataformat module): An exception is thrown during the logging call, and the log event is never delivered to its intended appender, only to Log4j's internal status logger.

Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue by sanitizing forbidden characters before XML output.