CVE-2026-81097

HIGHPre-NVD 8.48.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 8.4 from GitHub Security Advisory (severity: HIGH) published 2026-08-27. A secondary CVSS source baseline 8.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
8.4EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 8.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
8.4HIGHmedium confidence
EG Risk
38
EG Risk 38/100

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 (value × EchelonGraph’s weight)
Severity84% × 45%
The EG Score, 8.4 of 10.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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.
EPSS PROB
0.2%
EPSS %ILE
13th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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

August 27, 2026

Last Modified

September 24, 2026

Advisory Details (4)

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

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
Web page

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

https://github.com/maquina-app/rails-mcp-server/releases
GitHub pull request 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
Web page

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 20× in last 7d / 97× 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 it from the CNA feed. 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). Most recent first.

Showing the most recent 99 of 164 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 65 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  2. 2026-10-13 06:23 UTCEG score recompute
  3. 2026-10-13 06:22 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  4. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  5. 2026-10-12 14:57 UTCEG score recompute
  6. 2026-10-11 19:20 UTCEG score recompute
  7. 2026-10-11 16:37 UTCEG score recompute
  8. 2026-10-11 13:55 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  10. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-10 15:12 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  12. 2026-10-10 01:56 UTCEG score recompute
  13. 2026-10-10 01:55 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  14. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  15. 2026-10-09 03:07 UTCEG score recompute
  16. 2026-10-09 03:07 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  17. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  18. 2026-10-08 01:20 UTCEG score recompute
  19. 2026-10-08 01:20 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  20. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  21. 2026-10-07 02:45 UTCEG score recompute
  22. 2026-10-07 02:45 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  23. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  24. 2026-10-06 13:49 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  25. 2026-10-06 00:54 UTCEG score recompute
Show 74 more
  1. 2026-10-06 00:54 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  2. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  3. 2026-10-05 08:35 UTCEG score recompute
  4. 2026-10-05 08:35 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  5. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  6. 2026-10-04 19:39 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  7. 2026-10-04 04:08 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  8. 2026-10-03 15:13 UTCEG score recompute
  9. 2026-10-03 15:13 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  10. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-03 01:46 UTCEG score recompute
  12. 2026-10-03 01:46 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  13. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  14. 2026-10-02 12:50 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  15. 2026-10-01 22:32 UTCEG score recompute
  16. 2026-10-01 22:32 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  18. 2026-10-01 08:50 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  19. 2026-09-30 19:55 UTCEG score recompute
  20. 2026-09-30 19:55 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  21. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  22. 2026-09-30 05:03 UTCEG score recompute
  23. 2026-09-30 05:03 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  24. 2026-09-29 12:16 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  25. 2026-09-28 22:26 UTCEG score recompute
  26. 2026-09-28 22:26 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  27. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  28. 2026-09-28 09:30 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  29. 2026-09-27 20:35 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  30. 2026-09-27 07:40 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  31. 2026-09-26 18:45 UTCEG score recompute
  32. 2026-09-26 18:45 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  33. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  34. 2026-09-25 10:09 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  35. 2026-09-24 21:14 UTCEG score recompute
  36. 2026-09-24 21:14 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  37. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  38. 2026-09-24 09:11 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  39. 2026-09-23 20:16 UTCEG score recompute
  40. 2026-09-23 20:16 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  41. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  42. 2026-09-23 07:21 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  43. 2026-09-22 18:25 UTCEG score recompute
  44. 2026-09-22 18:25 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  45. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  46. 2026-09-22 04:26 UTCEG score recompute
  47. 2026-09-22 04:26 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  48. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  49. 2026-09-21 15:31 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  50. 2026-09-21 02:35 UTCEG score recompute
  51. 2026-09-21 02:35 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  52. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  53. 2026-09-20 13:36 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  54. 2026-09-20 00:41 UTCEG score recompute
  55. 2026-09-20 00:41 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  56. 2026-09-19 11:44 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  57. 2026-09-18 22:47 UTCEG score recompute
  58. 2026-09-18 22:47 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  59. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  60. 2026-09-18 09:51 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  61. 2026-09-17 20:55 UTCEG score recompute
  62. 2026-09-17 20:55 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  63. 2026-09-17 03:24 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  64. 2026-09-16 14:28 UTCEG score recompute
  65. 2026-09-16 14:28 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  66. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  67. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  68. 2026-09-16 01:31 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  69. 2026-09-15 12:36 UTCEG score recompute
  70. 2026-09-15 12:35 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  71. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  72. 2026-09-14 23:38 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  73. 2026-09-14 10:12 UTCGHSA enrichmentGHSA-247c-497m-jx82 · GitHub severity HIGH · GitHub CVSS 8.4
  74. 2026-09-13 21:17 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81097?
CVE-2026-81097 is a high-severity vulnerability; its CVE record was 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 made public?
CVE-2026-81097 was made public on August 26, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 27, 2026. EchelonGraph's copy of the record carries a last-modified date of September 24, 2026; the record at its source may have been updated since.
Is CVE-2026-81097 actively exploited?
CVE-2026-81097 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-81097?
CVE-2026-81097 has a CVSS base score of 8.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-81097?
A fix for CVE-2026-81097 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-81097 are linked in the Vendor Advisories panel on this page.

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