Description

CERT Polska has received a report about vulnerability in SzafirHost software and participated in coordination of its disclosure.

The vulnerability CVE-2026-44088: SzafirHost verifies the signature of the downloaded JAR file using class JarInputStream (reading from the beginning of the file), but loads classes using class JarFile/URLClassLoader (reading the Central Directory from the end). It can lead to remote code execution by allowing an attacker to combine a genuine, signed JAR file with a malicious ZIP file, causing the verification to pass but the malicious class to be loaded.

This issue was fixed in version 1.2.1.

Credits

We thank Mariusz Maik for the responsible vulnerability report.