Vulnerability · Published Jun 2, 2026 · Assigned by GitHub_M

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

High 8.0

In plain English

A high-severity incorrect authorization in alf.io from alfio-event. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities).

Severity (CVSS 3.1)8.0High

Exploit odds (30 days)0.3%top 79.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
alfio-event	alf.io	< 2.0-M5-2606

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

References

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