OpenS100 Portrayal Engine Unrestricted Lua Standard Library Access

published 2026-02-17 8 mo ago modified 2026-07-14 3 mo ago also EUVD-2026-7835

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits: 0; none known

OpenS100 (the reference implementation S-100 viewer) prior to commit 753cf29 contains a remote code execution vulnerability via an unrestricted Lua interpreter. The Portrayal Engine initializes Lua using luaL_openlibs() without sandboxing or capability restrictions, exposing standard libraries such as 'os' and 'io' to untrusted portrayal catalogues. An attacker can provide a malicious S-100 portrayal catalogue containing Lua scripts that execute arbitrary commands with the privileges of the OpenS100 process when a user imports the catalogue and loads a chart.

Patch / fix

links 1

github.com/S-100ExpertTeam/OpenS100@753cf29 commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 8 mo ago (2026-02-17)

Exploit prediction

1.08% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

mdpi.com https://www.mdpi.com/1424-8220/26/4/1246 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.4	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CNA	4.0	9.4	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

OpenS100 Project OpenS100

Classification

Weakness

CWE-749 Exposed Dangerous Method or Function
CWE-829 Inclusion of Functionality from Untrusted Control Sphere

References

github.com /S-100ExpertTeam/OpenS100/commit/753cf294434e8d3961f20a567c4d99151e3b530d
patch
mdpi.com /1424-8220/26/4/1246
technical-description, exploit
vulncheck.com /advisories/opens100-portrayal-engine-unrestricted-lua-standard-library-access
third-party-advisory

Sources

CVE List CVE-2026-22208
NVD CVE-2026-22208

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary