Floci: Code injection in API Gateway VTL mapping templates (RCE)

Summary

Floci, a local AWS emulator, contains a code injection flaw in its VTL template engine (VtlTemplateEngine) in versions 1.1.0 up to but not including 2.2.0. An unauthenticated attacker who can reach the Floci API can create a REST API with a MOCK integration whose Velocity template uses $util reflection to run operating system commands inside the Floci JVM. A public proof-of-concept exists, and CISA SSVC rates exploitation as PoC, automatable, with total technical impact.

Affected

• Floci 1.1.0 to before 2.2.0 (default configuration)
• Vendor and CVE record: versions before 2.2.0 are affected; third-party write-ups mention 2.2.1 as the fixed version

Fixed in

• Floci 2.2.0 (per CVE record and release tag)
• Some third-party sources recommend 2.2.1 or later; verify against the vendor advisory GHSA-3p4c-wp7w-mgjx

Workaround

• No vendor-published workaround found.
• Bind Floci to localhost only and do not expose port 4566 on shared, corporate, guest or cloud networks.
• Restrict access to the Floci port with host or network firewall rules.
• Run Floci in an isolated container or VM with minimal privileges and without access to production secrets or networks.

Exploitation

• Public proof-of-concept exploit available (CVE references).
• Metasploit module submitted as a pull request; merge status unconfirmed.
• Not listed in CISA KEV; no confirmed in-the-wild exploitation found in the sources checked.
• EPSS low (about 0.007 to 0.009).

Our recommendation

• Upgrade Floci to 2.2.1 or later (at minimum 2.2.0), and check the vendor advisory for the final fixed version.
• Identify all Floci instances, including developer workstations and CI runners, and check whether they are reachable from other networks.
• Remove network exposure of Floci port 4566 if not strictly needed.
• Review Floci's local state for unexpected REST APIs or integrations as a compromise indicator.
• Monitor the host running Floci for unusual child processes spawned by the Java process.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

Links to third-party sites, not checked by us – exploit code can contain malware. Only use it in isolated test environments.

• Proof of concept on GitHub (1 repositories) iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).
  Sidesploitx/CVE-2026-108598

Research sources

• GitHub Security Advisory GHSA-3p4c-wp7w-mgjx github.com
• Floci release 2.2.0 github.com
• Fix commit 144b90e6 github.com
• VulnCheck advisory www.vulncheck.com
• VtlTemplateEngine.java at commit 560b3e4 github.com
• OSV entry CVE-2026-108598 osv.dev

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 02:35.