Apache Tomcat Partial PUT RCE (CVE-2025-24813)
It is in KEV and attacks were seen within days, but exploitation needs the default servlet's write support turned on, which is off by default and rare; upgrade on your normal cycle and check that one setting.
Must act: Tomcat deployments where the DefaultServlet has readonly set to false, especially combined with file-based session persistence (PersistentManager + FileStore).
Can relax: The large majority of Tomcat users, who never enabled default-servlet writes, and anyone already on 9.0.99, 10.1.35, 11.0.3 or later.
- Check your version: run bin/version.sh (or catalina.sh version) and upgrade to 11.0.3, 10.1.35, 9.0.99 or later
- Check conf/web.xml and app web.xml files for the DefaultServlet readonly init-param set to false; remove it unless you truly need WebDAV-style uploads
- If writes must stay on, upgrade and avoid file-based session persistence in the default location