Authorization Flaw in alf.io (CVE-2026-35482)
Summary
Vulnerability in alf.io (CVE-2026-35482). Successful exploitation can lead to full system takeover. Exploitable via returnClass.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-35482 has been found in alf.io.
Attackers can target a specific entry point like returnClass over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.0/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "alf.io CVE-2026-35482" on the vendor's site.
CVE-2026-35482 (alf.io) — CWE-863 / CVSS v3 8.0
Attack vector: remote (network-reachable) / no user interaction
Attack surface: returnClass
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Incorrect authorization (CWE-863) exists in alf.io. Attackers reach the vulnerable code path via returnClass.
Check the vendor advisory for the affected versions of alf.io. Attack surface: returnClass.
Severity: High (CVSS 8.0/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'alf.io' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'alf.io' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
alf.ioを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov