Gearboy is a Game Boy, Game Boy Color, and Super Game Boy emulator and debugger with an embedded MCP server. Gearsystem, the affected component, has an optional --mcp-http mode that accepts unauthenticated MCP requests from any reachable network peer despite localhost-only documentation and logging. In the described platforms/shared/desktop/mcp/mcp_transport.h transport, the socket binds INADDR_ANY, normally on port 7777, and POST requests to /mcp reach dispatch without Authorization, Host, or Origin checks. Responses and OPTIONS advertise Access-Control-Allow-Origin: *. A peer can initialize an MCP session and invoke exposed emulator/debugging operations; even a garbage bearer token does not block dispatch, while a loopback-bind negative control prevents network access. The reported impact is bounded to the emulator process, debugging state, and local files accepted as media, rather than demonstrated host code execution. Gearboy 3.8.7 contains a patch.
CVE-2026-61542
“—” beside the score: it is equal to the CVSS score beside it.
This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (23rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-112412 (ENISA EUVD)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 8.6
- EG Score
- 8.6HIGHmedium confidence
- EG Risk
- 70EG Risk 70/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity86% × 45%Impact severity (EG Severity): CVSS 8.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.3%
- EPSS %ILE
- 23rd
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.6): severity, escalated by confirmed exploitation. This CVE's 8.6 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.6 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-09). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 28, 2026
Last Modified
November 3, 2026
Advisory Details (3)
Auto-updated Oct 28, 2026Gearboy 3.8.7
Patch available: drhelius/Gearboy 3.8.7
https://github.com/drhelius/Gearboy/releases/tag/3.8.7commit e2ead98e2fac (drhelius/Gearboy)
Fix landed in drhelius/Gearboy commit e2ead98e2fac — awaiting tagged release
https://github.com/drhelius/Gearboy/commit/e2ead98e2fac41e9df5a499e9e421c6a0e73f1bcGearsystem MCP HTTP transport binds all interfaces without authentication while documented as localhost · Advisory · drhelius/Gearboy · GitHub
https://github.com/drhelius/Gearboy/security/advisories/GHSA-fmvx-487g-mrwwWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 17× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
- 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-10 01:54 UTCEchelonGraph re-scored
- 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-03 14:30 UTCEchelonGraph re-scored
- 2026-11-03 14:19 UTCEchelonGraph re-scored
- 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
- 2026-10-28 20:27 UTCEchelonGraph re-scored
- 2026-10-28 20:01 UTCENISA EUVD ID recordedEUVD-2026-112412 · Source: ENISA EUVD
- 2026-10-28 19:53 UTCEchelonGraph re-scoredFirst assessed: 8.6 HIGH
- 2026-10-28 19:53 UTCMITRE cvelistV5first tracked
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Frequently asked(5)
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