rails-mcp-server 1.4.0 through 1.6.0 OS Command Execution via execute_ruby PTY Escape
Published Aug 27, 2026
8.6
HIGHCVSS 4.0
EPSS 0.24%
Description
The execute_ruby tool is documented as a read-only Ruby sandbox and is enforced by a pattern denylist together with replacements for the process-spawning methods on Kernel. The pseudo-terminal library's spawn entry points are neither in the denylist nor replaced, so a normal tool call could reach them and start a shell, executing commands as the account running the server and outside the guarded methods. The denylist was introduced with the tool in 1.4.0 and never covered those entry points through 1.6.0. Version 1.6.1 restricts the requires the sandbox permits to a data-only list and blocks dynamic dispatch to execution entry points; 2.0.0 removes the tool.
Affected products
-
- Version 1.4.0StatusaffectedConstraints<=1.6.0
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Maquina-App | Rails-Mcp-Server | unaffected |
|
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
1 other source (NVD) ▾
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
TotalDecision
n/aAssessed Aug 27, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Aug–Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.24% (0.00235) | 13.12th | v5 (v2026.06.15) |
| Aug 28, 2026 | 0.17% (0.00172) | 6.74th | v5 (v2026.06.15) |
References (4)
- https://github.com/maquina-app/rails-mcp-server product
- https://github.com/maquina-app/rails-mcp-server/pull/59 issue-trackingpatch
- https://github.com/maquina-app/rails-mcp-server/releases release-notes
- https://www.vulncheck.com/advisories/rails-mcp-server-1.4.0-through-1.6.0-os-command-execution-via-execute-ruby-pty-escape third-party-advisory
| Link | Providers | Tags |
|---|---|---|
| https://github.com/maquina-app/rails-mcp-server | product | |
| https://github.com/maquina-app/rails-mcp-server/pull/59 | issue-trackingpatch | |
| https://github.com/maquina-app/rails-mcp-server/releases | release-notes | |
| https://www.vulncheck.com/advisories/rails-mcp-server-1.4.0-through-1.6.0-os-command-execution-via-execute-ruby-pty-escape | third-party-advisory |
Change history (0)
No recorded changes yet.