CVE-2026-81097

HIGHPre-NVD 8.48.4—
EchelonGraph scoreHIGH confidence

Score 8.4 from GitHub Security Advisory (severity: HIGH) published 2026-08-27. the CNA's CVSS baseline 8.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 4 sources updated this week
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.4Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.4
EG Score
8.4(high)
EG Risk
38(Track)
EG Risk 38/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity84% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

August 27, 2026

Last Modified

August 29, 2026

Advisory Details (4)

Auto-updated Aug 27, 2026
Patch available. Sources: github_pr.
generic

rails-mcp-server 1.4.0 through 1.6.0 OS Command Execution via execute_ruby PTY Escape | Advisories | VulnCheck

https://www.vulncheck.com/advisories/rails-mcp-server-1.4.0-through-1.6.0-os-command-execution-via-execute-ruby-pty-escape
generic

Releases · maquina-app/rails-mcp-server · GitHub

https://github.com/maquina-app/rails-mcp-server/releases
github_pr Patch Available

Close execute_ruby process-execution vector (PTY + dynamic dispatch)

Patch available: maquina-app/rails-mcp-server v1.6.1 (PR #59 merged 2026-08-04)

https://github.com/maquina-app/rails-mcp-server/pull/59
generic

GitHub - maquina-app/rails-mcp-server: A Ruby gem implementation of a Model Context Protocol (MCP) server for Rails projects. This server allows LLMs (Large Language Models) to interact with Rails projects through the Model Context Protocol. · GitHub

https://github.com/maquina-app/rails-mcp-server

Vendor Advisories for CVE-2026-81097(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 15× in last 7d / 15× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-30 00:54 UTCGHSA enrichment
  3. 2026-08-29 11:59 UTCEG score recompute
  4. 2026-08-29 11:59 UTCGHSA enrichment
  5. 2026-08-29 09:40 UTCEG score recompute
  6. 2026-08-29 09:40 UTCGHSA enrichment
  7. 2026-08-28 21:42 UTCEPSS rescore
  8. 2026-08-28 20:43 UTCEG score recompute
  9. 2026-08-28 20:43 UTCGHSA enrichment
  10. 2026-08-28 19:22 UTCGHSA enrichment
  11. 2026-08-28 06:24 UTCEG score recompute
  12. 2026-08-28 06:24 UTCGHSA enrichment
  13. 2026-08-27 17:27 UTCEG score recompute
  14. 2026-08-27 16:47 UTCEG score recompute
  15. 2026-08-27 16:43 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81097?
CVE-2026-81097 is a high vulnerability published on August 27, 2026. 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…
When was CVE-2026-81097 disclosed?
CVE-2026-81097 was first published in the National Vulnerability Database on August 27, 2026, with the most recent update on August 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81097 actively exploited?
CVE-2026-81097 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 93.3% of all scored CVEs.
What is the CVSS score of CVE-2026-81097?
CVE-2026-81097 has a CVSS v4.0 base score of 8.4 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-81097?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81097, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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