CVE-2020-9484

When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to
9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to
control the contents and name of a file on the server; and b) the server is
configured to use the PersistenceManager with a FileStore; and c) the
PersistenceManager is configured with
sessionAttributeValueClassNameFilter=“null” (the default unless a
SecurityManager is used) or a sufficiently lax filter to allow the attacker
provided object to be deserialized; and d) the attacker knows the relative
file path from the storage location used by FileStore to the file the
attacker has control over; then, using a specifically crafted request, the
attacker will be able to trigger remote code execution via deserialization
of the file under their control. Note that all of conditions a) to d) must
be true for the attack to succeed.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=961209&gt;