CVE-2026-61500

Name of the Vulnerable Software and Affected Versions Rejetto HFS versions 3.0.0 through 3.2.0

Description Rejetto HFS uses a non-cryptographic pseudo-random number generator, Math.random(), to derive its session-cookie signing key. The application discloses outputs from this same generator to unauthenticated clients during the login process. A remote attacker can collect a small number of login responses to reconstruct the generator's state and recover the signing key. This allows the attacker to forge a valid administrator session cookie, gaining full administrative access. Once authenticated, the attacker can achieve remote code execution by utilizing the server code configuration feature, which allows the server to load JavaScript for plugin-style behavior. This issue has been exploited in the wild, with active scanning and exploitation attempts observed targeting hosts in the United States and Japan.

Recommendations Update Rejetto HFS to version 3.2.1 or later. As a temporary mitigation, restrict access to the web interface via firewall rules to allow only trusted IP addresses. As a temporary mitigation, place the server behind a reverse proxy with additional authentication.