What’s Vulnerable › Vulnerabilities

CVE-2026-35482: alf.io has an Authenticated RCE via Extension Script Sandbox Escape

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-06-02 · updated 2026-08-12
• Weakness: CWE-863

Description

alf.io is an open source ticket reservation system for conferences, trade shows, workshops, and meetups. Prior to version 2.0-M5-2606, a sandbox escape vulnerability in the alf.io extension script engine allows an authenticated administrator to execute arbitrary operating system commands on the server. The extension system is intended to execute restricted JavaScript in a sandboxed Rhino environment; however, a combination of an unguarded injected Java object (`returnClass`) and an incomplete AST blocklist allows the sandbox to be fully escaped using Java reflection without triggering any validation errors. Version 2.0-M5-2606 patches the issue.

Affected products

• alfio-event alf.io: before 2.0-M5-2606 — fixed in 2.0-M5-2606

How to fix

Upgrade to a fixed version: alfio-event alf.io 2.0-M5-2606. Check the vendor advisory for mitigations.

References

• https://github.com/alfio-event/alf.io/security/advisories/GHSA-3w8f-mcf6-cm7h
• https://github.com/alfio-event/alf.io/security/advisories/GHSA-3w8f-mcf6-cm7h

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