CVE-2020-17531: Deserialization flaw in EOL Tapestry 4.

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 10.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-12-08 · updated 2026-06-17
Weakness: CWE-502

Description

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.

Affected products

Apache Software Foundation Apache Tapestry: from 4.0.0 before 5.0.1 — fixed in 5.0.1

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Tapestry 5.0.1. Check the vendor advisory for mitigations.

References

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