Apache Tapestry 3.x allows deserialization of untrusted data, leading to remote code execution. This issue is similar to but distinct from CVE-2020-17531, which applies the the (also unsupported) 4.x version line. NOTE: This vulnerability only affects Apache Tapestry version line 3.x, which is no longer supported by the maintainer. Users are recommended to upgrade to a supported version line of Apache Tapestry.

A Java Serialization vulnerability was found in Apache Tapestry 4. Apache Tapestry 4 will attempt to deserialize the "sp" parameter even before invoking the page's validate method, leading to deserialization without authentication. Apache Tapestry 4 reached end of life in 2008 and no update to address this issue will be released. Apache Tapestry 5 versions are not vulnerable to this issue. Users of Apache Tapestry 4 should upgrade to the latest Apache Tapestry 5 version.