SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-35482

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.

CRITICAL 9.1EPSS 0.28%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.28%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1
9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS
0.28% probability · 21th percentile
CISA KEV
Not listed
Weakness
CWE-863
Affected
alf/alf
Source
security-advisories@github.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.